Performance Enhancement of Silicone Rubber Using Superhydrophobic Silica Aerogel with Robust Nanonetwork Structure and Outstanding Interfacial Effect

The application of high-performance rubber nanocomposites has attracted wide attention, but its development is limited by the imbalance of interface and network effects caused by fillers. Herein, an ultrastrong polymer nanocomposite is successfully designed by introducing a superhydrophobic and mesoporous silica aerogel (HSA) as the filler to poly(methyl vinyl phenyl) siloxane (PVMQ), which increased the PVMQ elongation at break (∼690.1%) by ∼9.3 times and the strength at break (∼6.6 MPa) by ∼24.3 times. Furthermore, HSA/PVMQ with a high dynamic storage modulus (G'0) of ∼12.2 MPa and high Payne effect (ΔG') of ∼9.4 MPa is simultaneously achieved, which is equivalent to 2-3 times that of commercial fumed silica reinforced PVMQ. The superior performance is attributed to the filler-rubber interfacial interaction and the robust filler-rubber entanglement network which is observed by scanning electron microscopy. When the HSA-PVMQ entanglement network is subjected to external stress, both the HSA and bound-PVMQ chains are synergistically involved in resisting structural evolution, resulting in the maximized energy dissipation and deformation resistance through the desorption of the polymer chain and the slip/interpenetrating of the exchange hydrogen bond pairs. Hence, highly aggregated nanoporous silica aerogels may soon be widely used in the application of reinforced silicone rubber or other polymers shortly.

Enhancing the Humidity Resistance of Triboelectric Nanogenerators: A Review

Triboelectric nanogenerators (TENGs) are sustainable energy resources for powering electronic devices from miniature to large-scale applications. However, their output performance and stability can deteriorate significantly when TENGs are exposed to moisture or humidity caused by the ambient environment or human physiological activities. This review provides an overview of the recent research advancements in enhancing the humidity resistance of TENGs. Various approaches have been reviewed including encapsulation techniques, surface modification of triboelectric materials to augment hydrophobicity or superhydrophobicity, the creation of fibrous architectures for effective moisture dissipation, leveraging water assistance for TENG performance enhancement, and other strategies like charge excitation. These research efforts contribute to the improvement of environmental adaptability and lead to expanded practical TENG applications both as energy harvesters and self-powered sensors. The efficacy of these strategies and future challenges are also discussed to facilitate the continued development of resilient TENGs in high humidity environments.

Biomimetic Multifunctional Graphene-Based Coating for Thermal Management, Solar De-Icing, and Fire Safety: Inspired from the Antireflection Nanostructure of Compound Eyes

Due to the ubiquitous and inexhaustible solar source, photothermal materials have gained considerable attention for their potential in heating and de-icing. Nevertheless, traditional photothermal materials, exemplified by graphene, frequently encounter challenges emanating from their elevated reflectance. Inspired by ocular structures, this study uses the Fresnel equation to enhance the photo-thermal conversion efficiency of graphene by introducing a polydimethylsiloxane (PDMS)/silicon dioxide (SiO2) coating, which reduces the light reflectance (≈20%) through destructive interference. The designed coating achieves an equilibrium temperature of ≈77 °C at one sun and a quick de-icing in ≈65 s, all with a thickness of 5 µm. Simulations demonstrate that applying this coating to high-rise buildings results in energy savings of ≈31% in winter heating. Furthermore, the combination of PDMS/SiO2 and graphene confers a notable enhancement in thermal stability through a synergistic flame-retardant mechanism, effectively safeguarding polyurethane against high temperatures and conflagrations, leading to marked reduction of 58% and 28% in heat release rate and total heat release. This innovative design enhances the photo-thermal conversion, de-icing function, and flame retardancy of graphene, thereby advancing its applications in outdoor equipment, high-rise buildings, and aerospace vessels.

Intermediate Polymer Relaxation Explains the Anomalous Rheology of Nanocomposites with Ultrasmall Attractive POSS Nanoparticles

The rheological properties of entangled polymers loaded with very small, strongly attractive polyhedral oligomeric silsesquioxane (POSS) fillers differ from that of nanocomposites with larger fillers by (1) the shorter breadth of the entanglement plateau and (2) the relatively unchanged terminal viscosity with increasing POSS loading. Although such anomalous rheological properties can rewrite the property-processing map of materials (e.g., high glass transition temperature and low viscosity), their mechanism remains unclear. In this study, we report that polymer relaxations on intermediate time scales between α and entire-chain relaxation, so-called "slower processes", are responsible for this unusual rheological behavior of poly(2-vinylpyridine)/octa(aminophenyl)silsesquioxane (P2VP/OAPS) nanocomposites. To uncover the effects of entanglements on the nanocomposite dynamics, rheometry is used for variable matrix molecular weights. Results show a systematic change in the rheological response, which is independent of the molecular weight, and in turn, the presence of entanglements. This supports a physical interpretation that a slower process dominates the rheological response of the material at intermediate frequencies on length scales larger than the segment length or the OAPS diameter, while the underlying physical time scales associated with the entanglement relaxation remain unchanged. Such insights are anticipated to assist the future rational design of other highly attractive and ultrasmall nanoparticles that enable a fine-tuned rheological response of nanocomposites across multiple length scales.

Ultrahigh Capacitive Energy Density in Stratified 2D Nanofiller-Based Polymer Dielectric Films

Dielectric capacitors are critical components in electronics and energy storage devices. The polymer-based dielectric capacitors have the advantages of device flexibility, fast charge-discharge rates, low loss, and graceful failure. Elevating the use of polymeric dielectric capacitors for advanced energy applications such as electric vehicles (EVs), however, requires significant enhancement of their energy densities. Here, we report a polymer thin film heterostructure-based capacitor of poly(vinylidene fluoride)/poly(methyl methacrylate) with stratified 2D nanofillers (Mica or h-BN nanosheets) (PVDF/PMMA-2D fillers/PVDF), that shows enhanced permittivity, high dielectric strength, and an ultrahigh energy density of ≈75 J/cm3 with efficiency over 79%. Density functional theory calculations verify the observed permittivity enhancement. This approach of using oriented 2D nanofillers-based polymer heterostructure composites is expected to be versatile for designing high energy density thin film polymeric dielectric capacitors for myriads of applications.

Emerging synthesis and characterization techniques for hybrid polymer nanocomposites

Metallic nanoparticles and carbon nanotubes are two of the most promising nanomaterials, due to their distinctive properties occurring from spatial confinement of electron-hole pairs. The unique combination of metallic nanoparticles and carbon nanotubes (CNTs) in a polymer matrix offers unparalleled advantages, making them highly desirable in various fields. Advanced methods and techniques for synthesizing and characterizing hybrid metal-CNT-polymer nanocomposites have undergone significant progress in recent years, paving their integration into various fields, including aerospace, electronics, energy, water treatment and environmental remediation. These advances have allowed better understanding of nanocomposite properties and imparted ability to tune specific properties through size, shape, and distribution control of the nanofillers within the matrix material or by altering filler properties through functionalization. This study aims to critically judge the emerging tools, techniques and methods used in polymer nanocomposites with specific focus on metal-CNT based hybrid polymer nanocomposites, and suggest new avenues for research in the field. Furthermore, by examining the mechanisms affecting the performance of these composites, we can understand how the inclusion of fillers alters the microstructure and overall behavior of the material. Ultimately, this knowledge could lay the foundation for the development of novel nanocomposites with tailored properties and enhanced performance in a plethora of applications.

Water-Soluble Nanocomposites Containing Co3O4 Nanoparticles Incorporated in Poly-1-vinyl-1,2,4-triazole

New water-soluble nanocomposites with cobalt oxide nanoparticles (Co₃O₄NPs) in a poly(1-vinyl-1,2,4-triazole) (PVT) matrix have been synthesized. The PVT used as a stabilizing polymer matrix was obtained by radical polymerization of 1-vinyl-1,2,4-triazole (VT). The polymer nanocomposites with Co₃O₄ nanoparticles were characterized by ultraviolet-visible, Fourier-transform infrared spectroscopy, atomic absorption spectroscopy, transmission electron microscopy, dynamic light scattering, gel permeation chromatography, and simultaneous thermogravimetric analysis. The resulting polymer nanocomposites consist of spherical isolated cobalt nanoparticles with a diameter of 1 to 13 nm. The average hydrodynamic diameters of macromolecular coils are 15-112 nm. The cobalt content in nanocomposites ranges from 1.5 to 11.0 wt.%. The thermal stability of nanocomposites is up to 320 °C.

Synthesis and DC Electrical Conductivity of Nanocomposites Based on Poly(1-vinyl-1,2,4-triazole) and Thermoelectric Tellurium Nanoparticles

In this work, the structural characteristics and DC electrical conductivity of firstly synthesized organic-inorganic nanocomposites of thermoelectric Te⁰ nanoparticles (1.4, 2.8, 4.3 wt%) and poly(1-vinyl-1,2,4-triazole) (PVT) were analyzed. The composites were characterized by high-resolution transmission electron microscopy, X-ray diffractometry, UV-Vis spectroscopy, and dynamic light scattering analysis. The study results showed that the nanocomposite nanoparticles distributed in the polymer matrix had a shape close to spherical and an average size of 4-18 nm. The average size of the nanoparticles was determined using the Brus model relation. The optical band gap applied in the model was determined on the basis of UV-Vis data by the Tauc method and the 10% absorption method. The values obtained varied between 2.9 and 5.1 nm. These values are in good agreement with the values of the nanoparticle size, which are typical for their fractions presented in the nanocomposite. The characteristic sizes of the nanoparticles in the fractions obtained from the Pesika size distribution data were 4.6, 4.9, and 5.0 nm for the nanocomposites with percentages of 1.4, 2.8, and 4.3%, respectively. The DC electrical conductivity of the nanocomposites was measured by a two-probe method in the temperature range of 25-80 °C. It was found that the formation of an inorganic nanophase in the PVT polymer as well as an increase in the average size of nanoparticles led to an increase in the DC conductivity over the entire temperature range. The results revealed that the DC electrical conductivity of nanocomposites with a Tellurium content of 2.8, 4.3 wt% at 80 °C becomes higher than the conventional boundary of 10^-10 S/cm separating dielectrics and semiconductors.

Supramolecular Assembly and Microscopic Dynamics Modulation of Nanoscale Inorganic Cryptand and Polymer Complex for Versatile Design of Flexible Single-Ion Conductors

The popular design of solid-state electrolytes (SSEs) from the chain relaxation of polymers faces the trade-offs among ion conductivity, stability, and processability. Herein, 2 nm inorganic cryptand molecules with the capability to carry different types of cations, including Ag⁺, Na⁺, K⁺, and Ca²⁺, are complexed with cationic polymers via ionic interaction, respectively, and the hybrid materials further phase separate into lamellar or hexagonal columnar structures. The successful establishment of ordered structures with ion channels from the packing of inorganic cryptands confers SSEs' excellent ionic conductivity to versatile types of cations. Meanwhile, suggested from the combination of broad dielectric spectroscopy, rheology, and thermal analysis, the fast chain relaxation can activate the dynamics of inorganic cryptand molecules and facilitate the ion hopping process in ion channels. The supramolecular interaction in the complex enables the highly flexible physical appearance for defect-free contact with electrodes as well as cost-effective processability and recyclability.

Linking Interfacial Bonding and Thermal Conductivity in Molecularly-Confined Polymer-Glass Nanocomposites with Ultra-High Interfacial Density

Thermal transport in polymer nanocomposites becomes dependent on the interfacial thermal conductance due to the ultra-high density of the internal interfaces when the polymer and filler domains are intimately mixed at the nanoscale. However, there is a lack of experimental measurements that can link the thermal conductance across the interfaces to the chemistry and bonding between the polymer molecules and the glass surface. Characterizing the thermal properties of amorphous composites are a particular challenge as their low intrinsic thermal conductivity leads to poor measurement sensitivity of the interfacial thermal conductance. To address this issue here, polymers are confined in porous organosilicates with high interfacial densities, stable composite structure, and varying surface chemistries. The thermal conductivities and fracture energies of the composites are measured with frequency dependent time-domain thermoreflectance (TDTR) and thin-film fracture testing, respectively. Effective medium theory (EMT) along with finite element analysis (FEA) is then used to uniquely extract the thermal boundary conductance (TBC) from the measured thermal conductivity of the composites. Changes in TBC are then linked to the hydrogen bonding between the polymer and organosilicate as quantified by Fourier-transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy. This platform for analysis is a new paradigm in the experimental investigation of heat flow across constituent domains.

Intensified Nonequilibrium Effect of Polymer Nanocomposites with Decreasing Nanoparticle Size

What are the most important and decisive parameters that determine the structure and the property of polymer nanocomposites (PNCs)? Previous studies answered that controlling the nanoparticle interface is critical, which can be achieved with a choice of a compatible nanoparticle, a proper surface modification, and a change in the polymer chain length. In addition to these parameters, the processing condition of PNCs has recently emerged as an influential parameter for controlling PNC properties, suggesting the existence of the nonequilibrium effect of PNCs. In this regard, we chose the solvent as a main change in the processing condition and investigated the initial solvent-driven nonequilibrium effect of PNCs with varied nanoparticle (NP) sizes. We found that the type of the initial solvent is indeed crucial in determining the ultimate properties of the PNCs, and this becomes more influential as the size of NPs decreases. The decreasing size of NPs causes a conformational change in the adsorbed polymers from tightly packed layers to loosely dangling chains. This results in much greater differences in NP microstructures and rheological properties of PNCs, indicating a stronger nonequilibrium effect with smaller NPs.

One-Pot Synthesis of Dual Color-Emitting CDs: Numerical and Experimental Optimization towards White LEDs

Carbon Dots (CDs) are fluorescent carbon-based nanoparticles that have attracted increasing attention in recent years as environment-friendly and cost-effective fluorophores. An application that can benefit from CDs in a relatively short-term perspective is the fabrication of color-converting materials in phosphor-converted white LEDs (WLEDs). In this work we present a one-pot solvothermal synthesis of polymer-passivated CDs that show a dual emission band (in the green and in the red regions) upon blue light excitation. A purposely designed numerical approach enables evaluating how the spectroscopic properties of such CDs can be profitable for application in WLEDs emulating daylight characteristics. Subsequently, we fabricate nanocomposite coatings based on the dual color-emitting CDs via solution-based strategies, and we compare their color-converting properties with those of the simulated ones to finally accomplish white light emission. The combined numerical and experimental approach can find a general use to reduce the number of experimental trial-and-error steps required for optimization of CD optical properties for lighting application.

Printed Antifouling Electrodes for Biosensing Applications

Biosensors based on miniaturized, functional electrodes are of high potential for various biosensing applications, especially at the point-of-care setting among others. However, the sensor performance of such electrochemical devices is still strongly limited, especially due to surface fouling in complex sample fluids, such as blood serum. Electrode coatings based on conductive nanomaterials embedded in antifouling matrices offer a promising strategy to overcome this limitation. However, known composite coatings require long (typically >24 h) and complex fabrication processes, which pose a strong barrier for cost-effective mass manufacturing and successful commercialization. Here, we describe a novel polymer/carbon nanotube (CNT) composite coating that can be produced from an ink containing a photoreactive and antifouling copolymer as well as conductive CNTs using fast and highly scalable printing processes. Coatings were prepared on screen-printed electrodes and characterized using cyclic voltammetry (CV) and protein fouling experiments. The coatings offered an electroactive surface area (EASA) comparable to uncoated screen-printed electrodes and retained >90% of initial EASA after 1 h of exposure to concentrated bovine serum albumin solution, while uncoated electrodes decreased to <20% of initial EASA after the same treatment. Utilizing the universal crosslinking reaction of the polymer coating, antibodies against the inflammatory biomarker C-reactive protein (CRP) were photochemically immobilized on the electrodes. Functionalized electrodes were fabricated in <2 h and were successfully used to quantify nanogram-range concentrations of CRP spiked in undiluted human blood serum using a sandwich-immunoassay with electrochemical read-out, demonstrating the high potential of the platform for biosensing applications.

Effective Attenuation of Electromagnetic Waves by Synergetic Effect of α-Fe2O3 and MWCNT/Graphene in LDPE-Based Composites for EMI Applications

In this study, a polymer nanocomposite is synthesized using magnetic and conducting fillers for enhanced electromagnetic interference (EMI) shielding. Alfa-ferrite (α-Fe₂O₃) nanoparticles with minimal multiwalled carbon nanotube (MWCNT) as low as 5 weight % in combination with variable concentrations of graphene nanoplatelets (GNP) are used as fillers in low-density polyethylene (LDPE) polymer matrix. Nanofillers and the polymer matrix are characterized by various techniques such as XRD, SEM, color mapping, EDAX, TGA, etc. The EMI shielding efficiency of the LDPE-based nanocomposites is tested using Vector Network Analyzer (VNA). The results showed that composite with LDPE:MWCNT:GNP:α-FO-50:5:40:5 displayed enhanced EMI shielding (in X-band (8.2-12.4 GHz) compared to other concentrations studied. This is due to the superior ohmic, dielectric, and magnetic losses at this particular composition and to the synergism amongst the filler. An attenuation of 99.99% was achieved for 5% α-Fe₂O₃. The mechanistic aspects of the shielding are discussed using permittivity, conductivity, and attenuation.

A Sustainable Hydroxypropyl Cellulose-Nanodiamond Composite for Flexible Electronic Applications

Designing fully green materials for flexible electronics is an urgent need due to the growing awareness of an environmental crisis. With the aim of developing a sustainable, printable, and biocompatible material to be exploited in flexible electronics, the rheological, structural and charge transport properties of water-based hydroxypropyl cellulose (HPC)-detonation nanodiamond (DND) viscous dispersions are investigated. A rheological investigation disclosed that the presence of the DND affects the orientation and entanglement of cellulose chains in the aqueous medium. In line with rheological analyses, the NMR diffusion experiments pointed out that the presence of DND modifies the hydrodynamic behavior of the cellulose molecules. Despite the increased rigidity of the system, the presence of DND slightly enhances the ionic conductivity of the dispersion, suggesting a modification in the charge transport properties of the material. The electrochemical analyses, performed through Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS), revealed that the HPC-DND system is remarkably stable in the explored voltage range (-0.1 to +0.4 V) and characterized by a lowered bulk resistance with respect to HPC. Such features, coupled with the printability and filmability of the material, represent good requirements for the exploitation of such systems in flexible electronic applications.

Carbon Nanotube Migration in Melt-Compounded PEO/PE Blends and Its Impact on Electrical and Rheological Properties

In this work, the effects of MWCNT concentration and mixing time on the migration of multi-walled carbon nanotubes (MWCNTs) within polyethylene oxide (PEO)/polyethylene (PE) blends are studied. Two-step mixing used to pre-localize MWCNTs within the PE phase and subsequently to observe their migration into the thermodynamically favored PEO phase. SEM micrographs show that many MWCNTs migrated into PEO. PEO/PE 40:60 polymer blend nanocomposites with 3 vol% MWCNTs mixed for short durations exhibited exceptional electromagnetic interference shielding effectiveness (EMI SE) and electrical conductivity (14.1 dB and 22.1 S/m, respectively), with properties dropping significantly at higher mixing times, suggesting the disruption of percolated MWCNT networks within the PE phase. PE grafted with maleic anhydride (PEMA) was introduced as a compatibilizer to arrest the migration of MWCNTs by creating a barrier at the PEO/PE interface. For the compatibilized system, EMI SE and electrical conductivity measurements showed a peak in electrical properties at 5 min of mixing (15.6 dB and 68.7 S/m), higher than those found for uncompatibilized systems. These improvements suggest that compatibilization can be effective at halting MWCNT migration. Although utilizing differences in thermodynamic affinity to draw MWCNTs toward the polymer/polymer interface of polymer blend systems can be an effective way to achieve interfacial localization, an excessively low viscosity of the destination phase may play a major role in reducing the entrapment of MWCNTs at the interface.

Polymer Nanocomposite Dielectrics: Understanding the Matrix/Particle Interface

Polymer nanocomposite dielectrics possess exceptional electric properties that are absent in the pristine dielectric polymers. The matrix/particle interface in polymer nanocomposite dielectrics is suggested to play decisive roles on the bulk material performance. Herein, we present a critical overview of recent research advances and important insights in understanding the matrix/particle interfacial characteristics in polymer nanocomposite dielectrics. The primary experimental strategies and state-of-the-art characterization techniques for resolving the local property-structure correlation of the matrix/particle interface are dissected in depth, with a focus on the characterization capabilities of each strategy or technique that other approaches cannot compete with. Limitations to each of the experimental strategy are evaluated as well. In the last section of this Review, we summarize and compare the three experimental strategies from multiple aspects and point out their advantages and disadvantages, critical issues, and possible experimental schemes to be established. Finally, the authors' personal viewpoints regarding the challenges of the existing experimental strategies are presented, and potential directions for the interface study are proposed for future research.

Spontaneous Transformation of Biomedical Polymeric Silver Salt into a Nanocomposite: Physical-Chemical and Antimicrobial Properties Dramatically Depend on the Initial Preparation State

An antimicrobial polyacrylic silver salt (freshly prepared, stored for one year and model-aged) was studied by physical–chemical techniques for nanoparticle detection. In all cases, this salt represents a composite of radical-enriched macromolecules and silver(0) nanoparticles. As time passed, the initial small spherical nanoparticles were converted into larger non-spherical silver nanoparticles. The initial highly water-soluble antimicrobial solid nanocomposite almost loses its solubility in water and cannot be used as an antimicrobial agent. Unlike insoluble solid silver polyacrylate, its freshly prepared aqueous solution retains a liquid-phase consistency after one year as well as pronounced antimicrobial properties. The mechanism of these spontaneous and model-simulated processes was proposed. These results have attracted attention for officinal biomedicinal silver salts as complex radical-enriched nanocomposite substances; they also indicate contrasting effects of silver polymeric salt storing in solid and solution forms that dramatically influence antimicrobial activity.

Potentiometric pH Sensor Based on Flexible Screen-Printable Polyaniline Composite for Textile-Based Microfluidic Applications

Skin pH can be used for monitoring infections in a healing wound, the onset of dermatitis, and hydration in sports medicine, but many challenges exist in integrating conventional sensing materials into wearable platforms. We present the development of a flexible, textile-based, screen-printed electrode system for biosensing applications, and demonstrate flexible polyaniline (PANI) composite-based potentiometric sensors on a textile substrate for real-time pH measurement. The pH response of the optimized PANI/dodecylbenzene sulfonic acid/screen-printing ink composite is compared to electropolymerized and drop-cast PANI sensors via open circuit potential measurements. High sensitivity was observed for all sensors between pH 3-10, with a composite based on PANI emeraldine base, demonstrating sufficient response time and a linear sensitivity of -27.9 mV/pH. This exceeded prior flexible screen-printed pH sensors in which all parts of the sensor, including the pH sensing material, are screen-printed. Even better sensitivity was observed for a PANI emeraldine salt composite (-42.6 mV/pH), although the response was less linear. Furthermore, the sensor was integrated into a screen-printed microfluidic channel demonstrating sample isolation during measurement for wearable, micro cloth-based analytical devices. This is the first fully screen-printed flexible PANI composite pH sensor demonstrated on a textile substrate that can additionally be integrated with textile-based microfluidic channels.

Engineering Antimicrobial Polymer Nanocomposites: In Situ Synthesis, Disruption of Polymicrobial Biofilms, and In Vivo Activity

The increasing incidence of microbial infections and a limited arsenal of effective antibacterial and antifungal agents have entailed the need for new broad-spectrum therapeutics. Polymer-inorganic nanocomposites have emerged as an integral choice of antimicrobials but are limited by complicated synthesis, narrow-spectrum activity, and poor in vivo efficacy. Herein, chloride counterions of a nontoxic, moderately antibacterial polymer have been explored for in situ nanoprecipitation-based synthesis of water-soluble polymer-silver chloride nanocomposites. With the controlled release of silver ions, the nanocomposites were highly active against multidrug-resistant bacteria as well as fluconazole-resistant fungi. Alongside the elimination of metabolically inactive bacterial cells, the nanocomposites disrupted polymicrobial biofilms, unlike antibiotics and only silver-based ointments. This underlined the role of the engineered composite design, where the polymer interacted with the biofilm matrix, facilitating the penetration of nanoparticles to kill microbes. Further, the nanocomposite diminished Pseudomonas aeruginosa burden in mice skin infection (>99.9%) with no dermal toxicity proving its potential for clinical translation.

Symmetry-Breaking and Self-Sorting in Block Copolymer-Based Multicomponent Nanocomposites

Co-assembly of inorganic nanoparticles (NPs) and nanostructured polymer matrix represents an intricate interplay of enthalpic or entropic forces. Particle size largely affects the phase behavior of the nanocomposite. Theoretical studies indicate that new morphologies would emerge when the particles become comparable to the soft matrix's size, but this has rarely been supported experimentally. By designing a multicomponent blend composed of NPs, block copolymer-based supramolecules, and small molecules, a 3-D ordered lattice beyond the native BCP's morphology was recently reported when the particle is larger than the microdomain of BCP. The blend can accommodate various formulation variables. In this paper, when the particle size equals the microdomain size, a symmetry-broken phase appears in a narrow range of particle sizes and compositions, which we named the "train track" structure. In this phase, the NPs aligned into a 3-D hexagonal lattice and packed asymmetrically along the c axis, making the projection of the ac and the bc plane resemble train tracks. Computational studies show that the broken symmetry reduces the polymer chain deformation and stabilizes the metastable hexagonally perforated lamellar morphology. Given the mobility of the multicomponent blend, the system shows a self-sorting behavior: segregating into two macroscopic phases with different nanostructures based on only a few nanometers NP size differences. Smaller NPs form "train track" morphology, while larger NPs form a "simple hexagon" structure, where the NPs take a symmetric hexagonal arrangement. Detailed structural evolution and simulation studies confirm the systematic-wide cooperativity across different components, indicating the strong self-regulation of the multicomponent system.

Polymer-Magnetic Semiconductor Nanocomposites for Industrial Electronic Applications

Nanocomposite materials have acquired great importance, as have similar composite materials on a macroscopic scale, because the reinforcement complements the defects in the properties of the matrix, thus obtaining materials with better mechanical, thermal, and electrical properties, among others. At the same time, the importance and research of polymeric nanocomposites reinforced with nanoparticles of various types have grown. Among those that have stood out the most in the electronics industry are polymeric matrices reinforced with nanoparticles that present dual behavior, that is, both magnetic and semiconductor. This property has been very well used in developing electronic devices such as televisions, computers, and smartphones, which are part of everyday life. In this sense, this review presents a compilation of the synthetic methods to produce polymer nanocomposites with dual magnetic and semiconductor behavior and their potential applications within electronic fields and new relevant trends.

Tuning Interparticle Contacts and Transport Properties of Maghemite-Thermoset Nanocomposites by Applying Oscillating Magnetic Fields

Conductive nanofillers, if integrated in an organized manner, can improve the transport properties of polymer matrices without compromising on their light weight. However, the relationship between the particle assemblies and transport properties of such nanocomposites, especially the competing effects of connected nanofiller pathways compared to resistances at interparticle contacts, has not been quantitatively studied. In this work, with the model nanocomposite of maghemite nanoparticles in epoxy, a novel fabrication method has been demonstrated to align nanofillers and control the interparticle contact amount within such a nanofiller assembly, using nanoparticle surface functionalization and oscillating magnetic field application. The nanofiller assembly cross-sectional areas were measured by processing micro-CT images and compared with the measured electrical and thermal properties of the nanocomposites. In terms of thermal transport, when the nanofiller assembly cross-sectional area was small, the dominance of conductivity pathways was observed up to ∼4.7 vol %, while interfacial thermal resistance began to dominate when the nanofiller assembly cross-sectional area became larger than 2700 μm².

Thermal Degradation Kinetics Analysis of Ethylene-Propylene Copolymer and EP-1-Hexene Terpolymer

LLDPE is a less crystalline polymer with vast industrial and domestic applications. It is imperative to understand the synthesis, processing conditions, and thermal degradation mechanism of the co- as well as terpolymers. This paper reports the in-situ synthesis and thermal degradation studies of the ethylene-propylene copolymer and ethylene-propylene-1-hexene terpolymer and its nanocomposite with ZnAL LDH sheets. The 1-hexene dosing during the in-situ process influenced the product yield and immensely affected the thermal stability of the resultant polymer. One milliliter 1-hexene in-situ addition increased the product yield by 170 percent, while the temperature at 10 percent weight loss in TGA was dropped by about 60 °C. While only 0.3 weight percent ZnAL LDH addition in the terpolymer improved the thermal stability by 10 °C. A master plot technique and combined kinetics analysis (CKA) were deployed to access the thermal degradation mechanism of the synthesized polymers.

Diversifying Composition Leads to Hierarchical Composites with Design Flexibility and Structural Fidelity

Although significant progress has been made in the self-assembly of nanostructures, present successes heavily rely on precision in building block design, composition, and pair interactions. These requirements fundamentally limit our ability to synthesize macroscopic materials where the likelihood of impurity inclusion escalates and, more importantly, to access molecular-to-nanoscopic-to-microscopic-to-macroscopic hierarchies, since the types and compositions of building blocks vary at each stage. Inspired by biological blends and high-entropy alloys, we hypothesize that diversifying the blend's composition can overcome these limitations. Increasing the number of components increases mixing entropy, leading to the dispersion of different components and, as a result, enhances interphase miscibility, weakens the dependence on specific pair interactions, and enables long-range cooperativity. This hypothesis is validated in complex blends containing small molecules, block copolymer-based supramolecules, and nanoparticles/colloidal particles. Hierarchically structured composites can be obtained with formulation flexibility in the filler selection and blend composition. It is worth noting that, by adding small molecules, we can solve the size constraint that plagues traditional block copolymer/nanoparticle blends. Detailed characterization and simulation further confirm that each component is distributed to locally mediate unfavorable interactions, cooperatively mitigate composition fluctuations, and retain structural fidelity. Furthermore, the blends have sufficient mobility to access tunable microstructures without compromising the order of the nanostructure. Besides establishing a kinetically viable pathway to release current constraints in the composite design and to navigate uncertainties during structure formation over multiple length scales, the present study demonstrates that entropy-driven behaviors can be realized in systems beyond high-entropy alloys despite inherent differences between metal alloys and organic/inorganic hybrids.

Green Synthesis of Stable Nanocomposites Containing Copper Nanoparticles Incorporated in Poly-N-vinylimidazole

New stable nanocomposites with copper nanoparticles (CuNPs) in a polymer matrix have been synthesized by green chemistry. Non-toxic poly-N-vinylimidazole was used as a stabilizing polymer matrix and ascorbic acid was used as a reducing agent. The polymer CuNPs nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic absorption spectroscopy (AAS), and thermogravimetric analysis (TGA). It was shown, using the dynamic light scattering (DLS) method, that the hydrodynamic diameters of nanocomposites depend on the CuNPs content and are in an associated state in an aqueous medium. The copper content in nanocomposites ranges from 1.8 to 12.3% wt. The obtained polymer nanocomposites consist of isolated copper nanoparticles with a diameter of 2 to 20 nm with a spherical shape.

Mechanical Properties of PC-ABS-Based Graphene-Reinforced Polymer Nanocomposites Fabricated by FDM Process

This experimental study investigates the mechanical properties of polymer matrix composites containing nanofiller developed by fused deposition modelling (FDM). A novel polymer nanocomposite was developed by amalgamating polycarbonate-acrylonitrile butadiene styrene (PC-ABS) by blending with graphene nanoparticles in the following proportions: 0.2, 0.4, 0.6, and 0.8 wt %. The composite filaments were developed using a twin-screw extrusion method. The mechanical properties such as tensile strength, low-velocity impact strength, and surface roughness of pure PC-ABS and PC-ABS + graphene were compared. It was observed that with the addition of graphene, tensile strength and impact strength improved, and a reduction in surface roughness was observed along the build direction. These properties were analyzed to understand the dispersion of graphene in the PC-ABS matrix and its effects on the parameters of the study. With the 0.8 wt % addition of graphene to PC-ABS, the tensile strength increased by 57%, and the impact resistance increased by 87%. A reduction in surface roughness was noted for every incremental addition of graphene to PC-ABS. The highest decrement was seen for the 0.8 wt % addition of graphene reinforcement that amounted to 40% compared to PC-ABS.

Role of Adsorbed Polymers on Nanoparticle Dispersion in Drying Polymer Nanocomposite Films

Polymers adsorbed on nanoparticles (NPs) are important elements that determine the dispersion of NPs in polymer nanocomposite (PNC) films. While previous studies have shown that increasing the number of adsorbed polymers on NPs can improve their dispersion during the drying process, the exact mechanism remained unclear. In this study, we investigated the role of adsorbed polymers in determining the microstructure and dispersion of NPs during the drying process. Investigation of the structural development of NPs using the synchrotron vertical-small-angle X-ray scattering technique revealed that increasing polymer adsorption suppresses bonding between the NPs at later stages of drying, when they approach each other and come in contact. On the particle length scale, NPs with large amounts of adsorbed polymers form loose clusters, whereas those with smaller amounts of adsorbed polymers form dense clusters. On the cluster length scale, loose clusters of NPs with large amounts of adsorbed polymers build densely packed aggregates, while dense clusters of NPs with small amounts of adsorbed polymers become organized into loose aggregates. The potential for the quantitative control of NP dispersion in PNC films via modification of polymer adsorption was established in this study.

Novel Approaches to In-Situ ATR-FTIR Spectroscopy and Spectroscopic Imaging for Real-Time Simultaneous Monitoring Curing Reaction and Diffusion of the Curing Agent at Rubber Nanocomposite Surface

Here, we propose a novel attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy method for simultaneously monitoring the curing reaction and the diffusion behavior of curing agents at the surface of rubber in real-time. The proposed scheme was demonstrated by fluorine rubber (FKM) and FKM/carbon nanotube (CNT) nanocomposites with a target curing agent of triallyl-isocyanurate (TAIC). The broadening and the evolution of the C=O stretching of TAIC were quantitatively analyzed to characterize the reaction and the diffusion. Changes in the width of the C=O stretching indicated the reaction rate at the surface was even faster than that of the bulk as measured by a curemeter. The diffusion coefficient of the curing agent in the course of heating was newly calculated by the initial increase in the absorbance and our model based on Fickian diffusion. The diffusion coefficients of TAIC during curing were evaluated, and its temperature and filler dependency were identified. Cross-sectional ATR-FTIR imaging and in situ ATR-FTIR imaging measurements supported the hypothesis of the unidirectional diffusion of the curing agent towards the heated surface. It was shown that our method of in situ ATR-FTIR can monitor the degrees of cure and the diffusion coefficients of curing agents simultaneously, which cannot be achieved by conventional methods, e.g., rheological measurements.

Development of novel TPI/HDPE/CNTs ternary hybrid shape memory nanocomposites

In order to make up for the defects of trans-1,4-polyisoprene (TPI) shape memory polymer, TPI/high density polyethylene (HDPE) hybrid shape memory matrix was prepared from the perspective of matrix composition. The carbon nanotubes (CNTs) with excellent mechanical properties were introduced into the hybrid shape memory matrix. Due to the difference of the inherent properties and geometry of nano-fillers, the change of the content of nano-fillers directly affects the bonding state within the composites. Therefore, it is very important to choose the appropriate content. In order to give full play to the potential of thermodynamics of nano-filler, the TPI/HDPE/CNTs ternary hybrid shape memory nanocomposites were prepared by mechanical melt blending technology combined with dynamic vulcanization and hot-pressing forming technology. The addition of CNTs promotes the formation of the crystal structure of TPI and HDPE, and facilitates the energy transfer between different interface, which greatly improves the thermal conductivity and mechanical properties of the nanocomposites at the same time. The effect of the changes of filler content on the thermodynamic properties of the composite materials were revealed by series of tests. The results show that the CNTs act as nucleating agents in the crystallization region of TPI and HDPE. However, the excessive addition of CNTs can inhibit the formation of HDPE crystal structure. Meanwhile, the crystallinity of nanocomposites is also an important factor affecting its thermal conductivity. The specimens with the CNTs content of 0.5 wt% have excellent tensile resistance and cyclic recovery ability, and it can improve the shape recovery properties. Therefore, the nanocomposite with the CNTs content of 0.5 wt% has the best thermodynamic and shape memory properties.

Effects of Graphene Oxidation on Interaction Energy and Interfacial Thermal Conductivity of Polymer Nanocomposite: A Molecular Dynamics Approach

Interfacial characteristics of polymer nanocomposites represent a crucial aspect to understand their global properties and to evaluate the interaction between nanofillers and matrix. In this work we used a molecular dynamics (MD) approach to characterize the interfacial region at the atomistic scale of graphene-based polymer nanocomposites. Three different polymer matrixes were considered, polylactic acid (PLA), polypropylene (PP) and epoxy resin (EPO), which were reinforced with three types of graphene fillers: pristine graphene (G), graphene oxide (GO) and reduced graphene oxide (rGO). In particular, the compatibility of the nanofillers in polymer matrixes were evaluated in terms of the interaction energy, while the interfacial thermal resistance (Kapitza resistance) between matrices and fillers was calculated with a nonequilibrium molecular dynamics (NEMD) method. Results showed that the oxidation degree plays an important role on the studied properties of the interfacial region. In particular, it was observed that the Kapitza resistance is decreased in the oxidized graphene (GO and rGO), while interaction energy depended on the polarity of the polymer matrix molecules and the contribution of the Coulombic component.

Temperature Influence on PI/Si3N4 Nanocomposite Dielectric Properties: A Multiscale Approach

The interphase area appears to have a great impact on nanocomposite (NC) dielectric properties. However, the underlying mechanisms are still poorly understood, mainly because the interphase properties remain unknown. This is even more true if the temperature increases. In this study, a multiscale characterization of polyimide/silicon nitride (PI/Si₃N₄) NC dielectric properties is performed at various temperatures. Using a nanomechanical characterization approach, the interphase width was estimated to be 30 ± 2 nm and 42 ± 3 nm for untreated and silane-treated nanoparticles, respectively. At room temperature, the interphase dielectric permittivity is lower than that of the matrix. It increases with the temperature, and at 150 °C, the interphase and matrix permittivities reach the same value. At the macroscale, an improvement of the dielectric breakdown is observed at high temperature (by a factor of 2 at 300 °C) for NC compared to neat PI. The comparison between nano- and macro-scale measurements leads to the understanding of a strong correlation between interphase properties and NC ones. Indeed, the NC macroscopic dielectric permittivity is well reproduced from nanoscale permittivity results using mixing laws. Finally, a strong correlation between the interphase dielectric permittivity and NC breakdown strength is observed.

In vitro bio-interaction responses and hemocompatibility of nano-based linear low-density polyethylene polymer embedded with heterogeneous TiO2/ZnO nanocomposites for biomedical applications

An innovative nano-base polymer that scavenges radicals and reactive oxygen species exhibits potential antibacterial properties, which are crucial in the biomedical field, particularly in reducing nosocomial infections. However, the safety of this nano-based polymer, which has direct contact with the human system, has not been fully understood. The present study investigated the cytocompatibility and hemocompatibility responses of linear low-density polyethylene polymer (LLDPE) embedded with difference ratios of heterogeneous TiO₂/ZnO nanocomposites. Exposure of the blood and fibroblast cells to LLDPE/100Z and LLDPE/25T75Z/10% nanocomposite films for 48 and 72 h decreased their viability by less than 40%, compared with LLDPE, LLDPE/100T and LLDPE/25T75Z/5% nanocomposite films. It also presented possible cellular damage and cytotoxicity, which was supported by the findings from the significant release of extracellular lactate dehydrogenase profiles and cell survival assay Further observation using an electron microscope revealed that LLDPE films with heterogeneous 25T75Z/5% promoted cell adhesion. Moreover, no hemolysis was detected in all ratios of heterogeneous TiO₂/ZnO nanocomposite in LLDPE film as it was less than 0.2%, suggesting that these materials were hemocompatible. This study on LLDPE film with heterogeneous TiO₂/ZnO nanocomposites demonstrated favorable biocompatible properties that were significant for advanced biomedical polymer application in a hospital setting.

Improved thermal stability of antireflective moth-eye topography imprinted on PMMA/TiO2surface nanocomposites

The thermal stability of antireflective moth-eye topographical features fabricated by nanoimprint lithography on poly (methyl methacrylate) (PMMA) incorporating TiO₂nanoparticles is explored. The effect of nanoparticle load on the relaxation dynamics of the moth-eye nanostructure is evaluated via grazing incidence small angle x-ray scattering measurements byin situmonitoring the structural decay of the nanopatterns upon thermal annealing. It is demonstrated that the incorporation of TiO₂nanoparticles to the imprinted surface nanocomposite films delays greatly the pattern relaxation which, in turn, enhances the stability of the patterned topography even at temperatures well above the polymer glass transition (T_g). The improved thermal behavior of the antireflective films will significantly enhance their functionality and performance in light-trapping applications where temperatures typically rise, such as solar devices or solar glass panels.

Orthogonal Reconstruction of Upconversion and Holographic Images for Anticounterfeiting Based on Energy Transfer

Crosstalk-free reconstruction of multiple images within a single element can greatly boost the image capacity and information security. We herein demonstrate a viable approach by integrating upconversion and holographic images into a single holographic polymer nanocomposite. The holographic image is reconstructed through photopolymerization-induced phase separation under a 460 nm laser and identifiable under room light, while the upconversion image recognizable under a 980 nm laser is photopatterned via spatially photobleaching of the dye embedded in the upconversion nanoparticle (UCNP) shell under 365 nm light. To this end, the lanthanide-doped UCNP in the core/shell/shell nanostructure of NaYF₄:20%Yb³⁺,0.5%Tm³⁺@NaYF₄@SiO₂ is designed, and the dye, fluorescein isothiocyanate (FITC), is fixed in the outermost SiO₂ shell via the amine-isothiocyanate reaction and the subsequent sol-gel reaction. Energy transfer from the core of the UCNP to FITC embedded in the shell is critical to boosting the contrast of the upconversion image, which dials the emission color from blue to yellow-green. It is also found that the upconversion image can be brightened by increasing the UCNP content while the holographic image is weakened when the UCNP content is over 15 wt %. This study paves a new way toward advanced anticounterfeiting.

Efficient Heat Shielding of Steel with Multilayer Nanocomposite Thin Film

In an effort to protect metal substrates from extreme heat, polymer-clay multilayer thin films are studied as expendable thermal barrier coatings. Nanocomposite films with a thickness ranging from 2 to 35 μm were deposited on steel plates and exposed to the flame from a butane torch. The 35 μm coating, composed of 14 deposited bilayers of tris(hydroxymethyl)aminomethane (THAM)-buffered polyethylenimine (PEI) and vermiculite clay (VMT), decreased the maximum temperature observed on the back side of a 0.32 cm thick steel plate by over 100 °C when heated with a butane torch. Upon exposure to high temperature, the polymer and amine salt undergo pyrolysis and intumesce, subsequently forming a char and blowing gas. The char encases the nanoclay platelets, and a ceramic bubble is formed. The macro-scale bubble, in tandem with the nanocomposite coating properties, increases resistance to heat transfer into the underlying metal substrate. This heat shielding behavior occurs through radiative effects and low aggregate through-plane conductivity resulting from multilayer nanodomains and intumesced porosity (i.e., conduction through the gas as the film expands to form a ceramic bubble). These relatively thin and lightweight films could be used to protect important metal parts (in automobiles, aircraft, etc.) from fire-related damage or other types of transient high-temperature situations.

Effects of Electron Beam Irradiation on Mechanical and Thermal Shrinkage Properties of Boehmite/HDPE Nanocomposite Film

Nanocomposites comprising high-density polyethylene (HDPE) and boehmite (BA) nanoparticles were prepared by melt blending and subsequently irradiated with electrons. Electron irradiation of HDPE causes crosslinking and, in the presence of BA, generates ketone functional groups. The functional groups can then form hydrogen bonds with the hydroxyl groups on the surface of the BA. Additionally, if the BA is surface modified by vinyltrimethoxysilane (vBA), it can covalently bond with the HDPE by irradiation-induced radical grafting. The strong covalent bonds generated by electron beam irradiation allow the desirable properties of the nanofiller to be transferred to the rest of the nanocomposite. Since EB irradiation produces a great number of strong covalent bonds between vBA nanoparticles and HDPE, the modulus of elasticity, yield strength, and resistance to thermal shrinkage are enhanced by electron irradiation.

Methionine-Functionalized Graphene Oxide/Sodium Alginate Bio-Polymer Nanocomposite Hydrogel Beads: Synthesis, Isotherm and Kinetic Studies for an Adsorptive Removal of Fluoroquinolone Antibiotics

In spite of the growing demand for new antibiotics, in the recent years, the occurrence of fluoroquinolone antibiotics (as a curative agent for urinary tract disorders and respiratory problems) in wastewater have drawn immense attention. Traces of antibiotic left-overs are present in the water system, causing noxious impact on human health and ecological environments, being a global concern. Our present work aims at tackling the major challenge of toxicity caused by antibiotics. This study deals with the efficient adsorption of two commonly used fluoroquinolone (FQ) antibiotics, i.e., Ofloxacin (OFX) and Moxifloxacin (MOX) on spherical hydrogel beads generated from methionine‒functionalized graphene oxide/ sodium alginate polymer (abbreviated Met-GO/SA) from aqueous solutions. The composition, morphology and crystal phase of prepared adsorbents were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HR-TEM) and thermogravimetric analysis/differential thermogravimetry (TGA/DTG). Batch adsorption tests are followed to optimize the conditions required for adsorption process. Both functionalized and non-functionalized adsorbents were compared to understand the influence of several experimental parameters, such as, the solution pH, contact time, adsorbent dosage, temperature and initial concentration of OFX and MOX on adsorption. The obtained results indicated that the functionalized adsorbent (Met-GO/SA) showed a better adsorption efficiency when compared to non-functionalized (GO/SA) adsorbent. Further, the Langmuir isotherm was validated as the best fitting model to describe adsorption equilibrium and pseudo second-order-kinetic model fitted well for both types of adsorbate. The maximum adsorption capacities of Met-GO/SA were 4.11 mg/g for MOX and 3.43 mg/g for OFX. Thermodynamic parameters, i.e., ∆G°, ∆H° and ∆S° were also calculated. It was shown that the overall adsorption process was thermodynamically favorable, spontaneous and exothermic in nature. The adsorbents were successfully regenerated up to four cycles with 0.005 M NaCl solutions. Overall, our work showed that the novel Met-GO/SA nanocomposite could better contribute to the removal of MOX and OFX from the liquid media. The gel beads prepared have adequate features, such as simple handling, eco-friendliness and easy recovery. Hence, polymer gel beads are promising candidates as adsorbents for large-scale water remediation.

A Review on Polymer Nanocomposites and Their Effective Applications in Membranes and Adsorbents for Water Treatment and Gas Separation

Globally, environmental challenges have been recognised as a matter of concern. Among these challenges are the reduced availability and quality of drinking water, and greenhouse gases that give rise to change in climate by entrapping heat, which result in respirational illness from smog and air pollution. Globally, the rate of demand for the use of freshwater has outgrown the rate of population increase; as the rapid growth in town and cities place a huge pressure on neighbouring water resources. Besides, the rapid growth in anthropogenic activities, such as the generation of energy and its conveyance, release carbon dioxide and other greenhouse gases, warming the planet. Polymer nanocomposite has played a significant role in finding solutions to current environmental problems. It has found interest due to its high potential for the reduction of gas emission, and elimination of pollutants, heavy metals, dyes, and oil in wastewater. The revolution of integrating developed novel nanomaterials such as nanoparticles, carbon nanotubes, nanofibers and activated carbon, in polymers, have instigated revitalizing and favourable inventive nanotechnologies for the treatment of wastewater and gas separation. This review discusses the effective employment of polymer nanocomposites for environmental utilizations. Polymer nanocomposite membranes for wastewater treatment and gas separation were reviewed together with their mechanisms. The use of polymer nanocomposites as an adsorbent for toxic metals ions removal and an adsorbent for dye removal were also discussed, together with the mechanism of the adsorption process. Patents in the utilization of innovative polymeric nanocomposite membranes for environmental utilizations were discussed.

Effect of Nanoclay Particles on the Performance of High-Density Polyethylene-Modified Asphalt Concrete Mixture

Utilizing polymers for asphalt concrete (AC) mixture modification has many drawbacks that hinder its wide implementations for roadway construction. Recently, research on employing complementary materials, such as nanomaterials, to balance negative impacts of polymers while enhancing the AC mixture’s performance has received great attention. This study aimed to investigate the effect of incorporating nanoclay (NC) particles on the performance of a high-density polyethylene (HDPE)-modified AC mixture. A 60/70 asphalt binder was first modified with HDPE, and then NC particles were gradually added at a concentration of 1–4% by weight of the asphalt binder. The binders’ physical characteristics, storage stability, and chemical change were scrutinized. AC mixture performance, including pseudo-stiffness, moisture damage resistance, stripping susceptibility, and rutting tendency, was investigated. A statistical analysis on the experimental results was conducted using Kruskal–Wallis and Dunn tests. Test results showed that employing NC/HDPE significantly increased penetration index and thereby enhanced binder temperature sensitivity. Moreover, it prevented oxidation action and separation and, therefore, enhanced binder storage stability. Furthermore, incorporating NC amplified pseudo-stiffness and significantly improved resistance against moisture damage and stripping of HDPE-modified mixtures. Moreover, it improved both elastic (recoverable) and plastic (unrecoverable) deformations of mixtures. The most satisfactory results were attained when incorporating 3% of NC.

Performance Analysis of Reinforced Epoxy Functionalized Carbon Nanotubes Composites for Vertical Axis Wind Turbine Blade

Synthetic materials using epoxy resin and woven Kevlar fiber nanocomposites were fabricated in the presence of functionalized multiwalled carbon nanotubes (F-MWCNTs). Kevlar-reinforced epoxy nanocomposites were designed to manufacture a small blade of vertical axis wind turbines (VAWT). It is important to estimate the deflection of the versatile composite turbine blades to forestall the blades from breakage. This paper investigates the effect of F-MWCNTs on mechanics and deflection of reinforced epoxy composites. The outcomes show that the mixing of F-MWCNTs with epoxy resin using a sonication process has a significant influence on the mechanical properties. Substantial improvement on the deflections was determined based on finite element analysis (FEA). The vortices from the vertical axis wind turbines (VAWTs) blades have a negative impact on power efficiency, since small blades are shown to be effective in reducing tip vortexes within the aerospace field. To support the theoretical movement of the VAWT blade, modeling calculations and analyzes were performed with the ANSYS code package to achieve insight into the sustainability of epoxy nanocomposites for turbine blade applications below aerodynamic, gravitational, and centrifugal loads. The results showed that the addition of F-MWCNTs to epoxy and Kevlar has a significant effect on the bias estimated by finite element analysis. ANSYS analysis results showed lower deflection on the blade using epoxy with an additional of 0.50 wt.% of MWCNTs-COOH at tip speed ratios of 2.1, 2.6, and 3.1.

A Highly Efficient Ag Nanoparticle-Immobilized Alginate-g-Polyacrylonitrile Hybrid Photocatalyst for the Degradation of Nitrophenols

Herein, we report PAN-g-Alg@Ag-based nanocatalysts synthesis via in situ oxidative free-radical polymerization of acrylonitrile (AN) using Alg@Ag nanoparticles (Alg@Ag NPs). Various analytical techniques, including FTIR, XRD, SEM, TEM, UV-Vis, and DSC, were employed to determine bonding interactions and chemical characteristics of the nanocatalyst. The optimized response surface methodology coupled central composite design (RSM-CCD) reaction conditions were a 35-min irradiation time in a 70-mg L-1 2,4-dinitrophenol (DNP) solution at pH of 4.68. Here, DNP degradation was 99.46% at a desirability of 1.00. The pseudo-first-order rate constant (K1) values were 0.047, 0.050, 0.054, 0.056, 0.059, and 0.064 min-1 with associated half-life (t1/2) values of 14.74, 13.86, 12.84, 12.38, 11.74, 10.82, and 10.04 min that corresponded to DNP concentrations of 10, 20, 30, 40, 50, 60, and 70 mg L-1, respectively, in the presence of PAN-g-Alg@Ag (0.03 g). The results indicate that the reaction followed the pseudo-first-order kinetic model with an R2 value of 0.99. The combined absorption properties of PAN and Alg@Ag NPs on copolymerization on the surface contributed more charge density to surface plasmon resonance (SPR) in a way to degrade more and more molecules of DNP together with preventing the recombination of electron and hole pairs within the photocatalytic process.

Formation and Electrochemical Evaluation of Polyaniline and Polypyrrole Nanocomposites Based on Glucose Oxidase and Gold Nanostructures

Nanocomposites based on two conducting polymers, polyaniline (PANI) and polypyrrole (Ppy), with embedded glucose oxidase (GOx) and 6 nm size gold nanoparticles (AuNPs_(6nm)) or gold-nanoclusters formed from chloroaurate ions (AuCl₄⁻), were synthesized by enzyme-assisted polymerization. Charge (electron) transfer in systems based on PANI/AuNPs_(6nm)-GOx, PANI/AuNPs_(AuCl4⁻₎-GOx, Ppy/AuNPs_(6nm)-GOx and Ppy/AuNPs_(AuCl4⁻₎-GOx nanocomposites was investigated. Cyclic voltammetry (CV)-based investigations showed that the reported polymer nanocomposites are able to facilitate electron transfer from enzyme to the graphite rod (GR) electrode. Significantly higher anodic current and well-defined red-ox peaks were observed at a scan rate of 0.10 V s⁻¹. Logarithmic function of anodic current (log I_pa), which was determined by CV-based experiments performed with glucose, was proportional to the logarithmic function of a scan rate (log v) in the range of 0.699–2.48 mV s⁻¹, and it indicates that diffusion-controlled electrochemical processes were limiting the kinetics of the analytical signal. The most efficient nanocomposite structure for the design of the reported glucose biosensor was based on two-day formed Ppy/AuNPs_(AuCl4⁻₎-GOx nanocomposites. GR/Ppy/AuNPs_(AuCl4⁻₎-GOx was characterized by the linear dependence of the analytical signal on glucose concentration in the range from 0.1 to 0.70 mmol L⁻¹, the sensitivity of 4.31 mA mM cm⁻², the limit of detection of 0.10 mmol L⁻¹ and the half-life period of 19 days.

Fabrication of Highly Porous Polymeric Nanocomposite for the Removal of Radioactive U(VI) and Eu(III) Ions from Aqueous Solution

In the present study, a polymeric nanocomposite, CoFe2O4@DHBF, was fabricated using 2,4 dihydroxybenzaldehyde and formaldehyde in basic medium with CoFe2O4 nanoparticles. The fabricated nanocomposite was characterized using FTIR, TGA, XRD, SEM, TEM, and XPS analyses. The analytical results revealed that the magnetic nanocomposite was fabricated successfully with high surface area 370.24 m2/g. The fabricated CoFe2O4@DHBF was used as an efficient adsorbent for the adsorption of U(VI) and Eu(III) ions from contaminated water. pH, initial concentration, adsorption time, and the temperature of the contaminated water solution affecting the adsorption ability of the nanocomposites were studied. The batch adsorption results exposed that the adsorption capacity for the removal of U(VI) and Eu(III) was found to be 237.5 and 225.5 mg/g. The adsorption kinetics support that both the metal ions follow second order adsorption kinetics. The adsorption isotherm well fits with the Langmuir adsorption isotherm and the correlation coefficient (R2) values were found to be 0.9920 and 0.9913 for the adsorption of U(VI) and Eu(III), respectively. It was noticed that the fabricated nanocomposites show excellent regeneration ability and about 220.1 and 211.3 mg/g adsorption capacity remains with U(VI) and Eu(III) under optimum conditions.

Graphene/polymer nanocomposite degradation by ultraviolet light: The effects of graphene nanofillers and their potential for release

The ultraviolet (UV)-induced degradation of graphene/polymer nanocomposites was investigated in this study. Specifically, the effect of few-layer graphene nanofillers on the degradation of a thermoplastic polyurethane (TPU) and the release potential of graphene from the degraded nanocomposite surfaces were assessed. Graphene/TPU (G/TPU) nanocomposites and neat TPU were UV-exposed under both dry and humid conditions in the NIST SPHERE, a precisely controlled, high intensity UV-weathering device. Neat TPU and G/TPU were characterized over the time course of UV exposure using color measurements and infrared spectroscopy, for appearance and chemical changes, respectively. Changes in thickness and surface morphology were obtained with scanning electron microscopy. A new fluorescence quenching measurement approach was developed to identify graphene sheets at the nanocomposite surface, which was supported by contact angle measurements. The potential for graphene release from the nanocomposite surface was evaluated using a tape-lift method followed by microscopy of any particles present on the tape. The findings suggest that graphene improves the service life of TPU with respect to UV exposure, but that graphene becomes exposed at the nanocomposite surface over time, which may potentially lead to its release when exposed to small mechanical forces or upon contact with other materials.

Characteristics of Thermosetting Polymer Nanocomposites: Siloxane-Imide-Containing Benzoxazine with Silsesquioxane Epoxy Resins

A series of innovative thermosetting polymer nanocomposites comprising of polysiloxane-imide-containing benzoxazine (PSiBZ) as the matrix and double-decker silsesquioxane (DDSQ) epoxy or polyhedral oligomeric silsesquioxane (POSS) epoxy were prepared for improving thermosetting performance. Thermomechanical and dynamic mechanical characterizations indicated that both DDSQ and POSS could effectively lower the coefficient of thermal expansion by up to approximately 34% and considerably increase the storage modulus (up to 183%). Therefore, DDSQ and POSS are promising materials for low-stress encapsulation for electronic packaging applications.

Thermal Degradation of Polystyrene (PS) Nanocomposites Loaded with Sol Gel-Synthesized ZnO Nanorods

Thermal degradation of polystyrene/ZnO (PS/ZnO) nanocomposites was investigated in this study. PS/ZnO polymer nanocomposites were prepared by using ZnO nanorods as nanofillers that were prepared via the sol-gel route. The as-prepared ZnO nanoparticles showed nanocrystallites in rod-like shapes with a non-uniform hexagonal cross-section and diameter varying from 40 to 75 nm. PS/ZnO nanocomposites with ZnO nanoparticles content ranging from 0–3 wt% are prepared via the common casting method. Even dispersion for ZnO nanoparticles within as-prepared PS/ZnO nanocomposites was verified through SEM/EDX measurements. Thermal degradation of the samples was checked by using the thermogravimetric (TG) analysis and differential scanning calorimetry (DSC) under non-isothermal conditions and a constant heating rate of 10 °C min. The thermal stability of the nanocomposite is elevated compared to that of pristine PS due to the addition of the ZnO nanoparticles. The homogeneity of the PS/ZnO nanocomposites is verified by systematic increases in thermal degradation with increasing ZnO content. The characterization degradation temperatures at different weight loss percentages of ZnO nanoparticles increase at high ZnO wt%. Static activation energy of decomposing is based on TGA data. Activation energies showed some enhancement after the addition of ZnO nanorods into the PS matrix. Enhancing the thermal stability of PS with ZnO addition within the investigated ZnO concentration range is verified by TG, DSC results.

Considerations for and Guidance to Testing and Evaluating Migration/Release of Nanoparticles from Polymer Based Nanocomposites

The use of nanoadditives in food contact materials requires risk assessment to ensure consumers' safety. The evaluation of health risk is based on the combination of two elements: hazard and exposure. For nanomaterials (NM) used as additives in nanocomposites, the exposure is directly linked to the level of migration or release of the NM into the food. In principle, appropriate methods for experimental determination and theoretical estimation of migration are available but need diligent considerations to avoid erroneous conclusions from the measured data. We propose a comprehensive test scheme based on these methods, starting with characterization of the nanomaterial itself and when incorporated in the polymer. These data form the basis for making a decision whether migration of the NM can be excluded by migration theoretical considerations or if experimental migration testing and/or abrasion testing for mechanical release should be carried out. Guidance to and considerations for each of these steps and regarding the applicable methods are discussed. In conclusion, the results will provide a basis for risk assessment, either directly when exposure of consumers to the nanomaterials can be excluded or will be very low or, in the case of evidenced exposure, in combination with then needed toxicological data.

Mechanically Robust and Broadband Blackbody Composite Films Based on Self-Assembled Layered Structures

Inspired by nacre that is mechanically strong and versatile in light manipulation, large-scale black films with a nacre-like microstructure and carbon nanotube inclusion were prepared using a facile self-assembly technique. A layered structure promoting blackness and toughness simultaneously was realized, affording robust films with a solar-absorptivity as high as 96.9%. Our design strategy and fabrication process will be beneficial for the facile access to various advanced blackbody coatings.

X-ray-Based Spectroscopic Techniques for Characterization of Polymer Nanocomposite Materials at a Molecular Level

This review provides detailed fundamental principles of X-ray-based characterization methods, i.e., X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, and near-edge X-ray absorption fine structure, and the development of different techniques based on the principles to gain deeper understandings of chemical structures in polymeric materials. Qualitative and quantitative analyses enable obtaining chemical compositions including the relative and absolute concentrations of specific elements and chemical bonds near the surface of or deep inside the material of interest. More importantly, these techniques help us to access the interface of a polymer and a solid material at a molecular level in a polymer nanocomposite. The collective interpretation of all this information leads us to a better understanding of why specific material properties can be modulated in composite geometry. Finally, we will highlight the impacts of the use of these spectroscopic methods in recent advances in polymer nanocomposite materials for various nano- and bio-applications.