Polymer–Ceramic Nanohybrid Materials

Microbially Influenced Corrosion of Steel in Marine Environments: A Review from Mechanisms to Prevention

Microbially influenced corrosion (MIC) is a formidable challenge in the marine industry, resulting from intricate interactions among various biochemical reactions and microbial species. Many preventions used to mitigate biocorrosion fail due to ignorance of the MIC mechanisms. This review provides a summary of the current research on microbial corrosion in marine environments, including corrosive microbes and biocorrosion mechanisms. We also summarized current strategies for inhibiting MIC and proposed future research directions for MIC mechanisms and prevention. This review aims to comprehensively understand marine microbial corrosion and contribute to novel strategy developments for biocorrosion control in marine environments.

Interfacial Compatibility of Core-Shell Cellulose Nanocrystals for Improving Dynamic Covalent Adaptable Networks' Fracture Resistance in Nanohybrid Vitrimer Composites

The development of polymeric nanocomposites with dynamic covalent adaptable networks and biobased nanomaterials has been a promising approach toward sustainable advanced materials, enabling reprogramming and recycling capabilities. Herein, a core-shell nanohybrid of functionalized cellulose nanocrystals (CNCs) is explored to provide crucial interfacial compatibility for improving the covalent adaptable networks of epoxy-thiol vitrimers in fracture resistance. The poly(ε-caprolactone) (PCL) shells grafted from CNC surfaces can be cross-linked with the covalent adaptable networks via a hot-pressing transesterification process. According to the additive concentration and annealing temperature, the stress relaxation behavior of nanohybrid vitrimer composites can be effectively regulated by the core-shell PCL-grafted CNC (CNC-PCL) nanohybrids from a dispersed to cross-linked interaction. The addition of 15 wt % of the core-shell CNC-PCLs exhibits the reinforced improvement of nanohybrid vitrimer composites in the average Young's modulus of 2.5×, fracture stress of 5.4×, and fracture strain of 2.0×. The research findings might have profound implications for developing synergistic interfacial compatibility between dynamic vitrimer networks and functional nanoparticles for advanced polymeric nanocomposites.

Polymerization and Applications of Poly(methyl methacrylate)-Graphene Oxide Nanocomposites: A Review

Graphene oxide (GO)-incorporated poly(methyl methacrylate) (PMMA) nanocomposites (PMMA-GO) have demonstrated a wide range of outstanding mechanical, electrical, and physical characteristics. It is of interest to review the synthesis of PMMA-GO nanocomposites and their applications as multifunctional structural materials. The attention of this review is to focus on the radical polymerization techniques, mainly bulk and emulsion polymerization, to prepare PMMA-GO polymeric nanocomposite materials. This review also discusses the effect of solvent polarity on the polymerization process and the types of surfactants (anionic, cationic, nonionic) and initiator used in the polymerization. PMMA-GO nanocomposite synthesis using radical polymerization-based techniques is an active topic of study with several prospects for considerable future improvement and a variety of possible emerging applications. The concentration and dispersity of GO used in the polymerization play critical roles to ensure the functionality and performance of the PMMA-GO nanocomposites.

Interface damage and fracture mechanisms of a ceramic/polymer interface based on atomic-scale simulations

The performance of ceramic/polymer composite materials is significantly affected by their internal interfaces. To reveal the intrinsic interface fracturing mechanism of ceramic/polymer interfaces, an interfacial model composed of SiO₂ and polypropylene (PP) is investigated using the molecular dynamics method. The interface damage is quantified by the increase in the interface free volume and deformation of a single PP chain. As stretching speeds increase, the free volume and outflowing atoms of PP chains decrease with the same interfacial displacement, which results in the increase of the interface strength and fracture energy. At low stretching speeds, the interface damage mechanism is determined by a competition between attractions of the PP single chains from SiO₂ and PP. In contrast, at higher stretching speeds, the interface fracture is more brittle and the interface strength and fracture energy are both higher owing to the smaller cavity ratio. The results of this study contribute to an in depth understanding of the fracture mechanism of ceramic/polymer interfaces in many systems.

Porous Mixed-Metal Oxide Li-Ion Battery Electrodes by Shear-Induced Co-assembly of Precursors and Tailored Polymer Particles

Due to their various applications, metal oxides are of high interest for fundamental research and commercial usage. Per applications as catalysts or electrochemical devices, the tailored design of metal oxides featuring a high specific surface area and additional functionalities is of the utmost importance for the performance of the resulting materials. We report a new method for preparing free-standing films consisting of hierarchically porous metal oxides (titanium and niobium based) by combining emulsion polymerization and shear-induced monodisperse particle self-assembly in the presence of sol-gel precursors. After thermal treatment, the resulting porous materials can be used as electrodes in Li-ion batteries. The titanium and niobium sol-gel precursors were partially immobilized to the surface of organic core-interlayer particles featuring hydroxyl groups to obtain hybrid organic-inorganic particles through the melt-shear organization process. Free-standing particle-based films, in analogy to elastomeric opal films and colloidal crystals, can be prepared in a convenient one-step preparation process. After thermal treatment, ordered pores are obtained, while the pristine metal oxide precursor shell can be converted to the (mixed) metal oxide matrix. Heat treatment under CO₂ leads to mixed-TiNb oxide/carbon hybrid materials. The highly porous derivative structure enhances electrolyte permeation. When tested as Li-ion battery electrodes, it shows a specific capacity of 335 mAh·g^-1 at a rate of 10 mA·g^-1. After 1000 cycles at 250 mA·g^-1, the electrodes still provided a specific capacity of 191 mAh·g^-1.

Combining Soft Polysilazanes with Melt-Shear Organization of Core-Shell Particles: On the Road to Polymer-Templated Porous Ceramics

The preparation of ordered macroporous SiCN ceramics has attracted significant interest and is an attractive area for various applications, e.g., in the fields of catalysis, gas adsorption, or membranes. Non-oxidic ceramics, such as SiCN, own a great stability based on the covalent bonds between the containing elements, which leads to interesting properties concerning resistance and stability at high temperature. Their peculiar properties have become more and more important for a manifold of applications, like catalysis or separation processes, at high temperatures. Within this work, a feasible approach for the preparation of ordered porous materials by taking advantage of polymer-derived ceramics is presented. To gain access to free-standing films consisting of porous ceramic materials, the combination of monodisperse organic polymer-based colloids with diameters of 130 nm and 180 nm featuring a processable preceramic polymer is essential. For this purpose, the tailored design of hybrid organic/inorganic particles featuring anchoring sites for a preceramic polymer in the soft shell material is developed. Moreover, polymer-based core particles are used as sacrificial template for the generation of pores, while the preceramic shell polymer can be converted to the ceramic matrix after thermal treatment. Two different routes for the polymer particles, which can be obtained by emulsion polymerization, are followed for covalently linking the preceramic polysilazane Durazane1800 (Merck, Germany): (i) Free radical polymerization and (ii) atom transfer radical polymerization (ATRP) conditions. These hybrid hard core/soft shell particles can be processed via the so-called melt-shear organization for the one-step preparation of free-standing particle films. A major advantage of this technique is the absence of any solvent or dispersion medium, enabling the core particles to merge into ordered particle stacks based on the soft preceramic shell. Subsequent ceramization of the colloidal crystal films leads to core particle degradation and transformation into porous ceramics with ceramic yields of 18–54%.

Recent Trends in Metallopolymer Design: Redox-Controlled Surfaces, Porous Membranes, and Switchable Optical Materials Using Ferrocene-Containing Polymers

Metallopolymers with metal functionalities are a unique class of functional materials. Their redox-mediated optoelectronic and catalytic switching capabilities, their outstanding structure formation and separation capabilities have been reported recently. Within this Minireview, the scope and limitations of intriguing ferrocene-containing systems will be discussed. In the first section recent advances in metallopolymer design will be given leading to a plethora of novel metallopolymer architectures. Discussed synthetic pathways comprise controlled and living polymerization protocols as well as surface immobilization strategies. In the following sections, we focus on recent advances and new applications for side-chain and main-chain ferrocene-containing polymers as (i) remote-switchable materials, (ii) smart surfaces, (iii) redox-responsive membranes, and some recent trends in (iv) photonic structures and (v) other optical applications.

Microporosity and CO₂ Capture Properties of Amorphous Silicon Oxynitride Derived from Novel Polyalkoxysilsesquiazanes

Polyalkoxysilsesquiazanes ([ROSi(NH)_1.5]_n, ROSZ, R = Et, nPr, iPr, nBu, sBu, nHex, sHex, cHex, decahydronaphthyl (DHNp)) were synthesized by ammonolysis at −78 °C of alkoxytrichlorosilane (ROSiCl₃), which was isolated by distillation as a reaction product of SiCl₄ and ROH. The simultaneous thermogravimetric and mass spectrometry analyses of the ROSZs under helium revealed a common decomposition reaction, the cleavage of the oxygen–carbon bond of the RO group to evolve alkene as a main gaseous species formed in-situ, leading to the formation of microporous amorphous Si–O–N at 550 °C to 800 °C. The microporosity in terms of the peak of the pore size distribution curve located within the micropore size range (<2 nm) and the total micropore volume, as well as the specific surface area (SSA) of the Si–O–N, increased consistently with the molecular size estimated for the alkene formed in-situ during the pyrolysis. The CO₂ capture capacity at 0 °C of the Si–O–N material increased consistently with its SSA, and an excellent CO₂ capture capacity of 3.9 mmol·g⁻¹ at 0 °C and CO₂ 1 atm was achieved for the Si–O–N derived from DHNpOSZ having an SSA of 750 m²·g⁻¹. The CO₂ capture properties were further discussed based on their temperature dependency, and a surface functional group of the Si–O–N formed in-situ during the polymer/ceramics thermal conversion.

Free-Standing and Self-Crosslinkable Hybrid Films by Core-Shell Particle Design and Processing

The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a core-shell particle architecture. The synthesis of well-designed monodisperse core-shell particles by emulsion polymerization is the basic prerequisite for subsequent particle processing via the melt-shear organization technique. In more detail, the core particles consist of polystyrene (PS) or poly(methyl methacrylate) (PMMA), while the comparably soft particle shell consists of poly(ethyl acrylate) (PEA) and different alkoxysilane-based poly(methacrylate)s. For hybrid film formation and convenient self-cross-linking, different alkyl groups at the siloxane moieties were investigated in detail by solid-state Magic-Angle Spinning Nuclear Magnetic Resonance (MAS, NMR) spectroscopy revealing different crosslinking capabilities, which strongly influence the properties of the core or shell particle films with respect to transparency and iridescent reflection colors. Furthermore, solid-state NMR spectroscopy and investigation of the thermal properties by differential scanning calorimetry (DSC) measurements allow for insights into the cross-linking capabilities prior to and after synthesis, as well as after the thermally and pressure-induced processing steps. Subsequently, free-standing and self-crosslinked particle-based films featuring excellent particle order are obtained by application of the melt-shear organization technique, as shown by microscopy (TEM, SEM).

Young's modulus and Poisson's ratio for TiO2-based nanotubes and nanowires: modelling of temperature dependence

The temperature dependence of the Young's modulus and Poisson's ratio of a number of TiO₂-based four-facetted nanotubes and nanowires are predicted through the calculation of the Helmholtz free energy.

One for all: cobalt-containing polymethacrylates for magnetic ceramics, block copolymerization, unexpected electrochemistry, and stimuli-responsiveness

Functional cobalt-containing homo and block polymers are probed with respect to their redox-induced switchability and as preceramic materials.

A convenient synthesis strategy for microphase-separating functional copolymers: the cyclohydrocarbosilane tool box

Functional polyhydrocarbosilane-based homo and diblock copolymers are prepared by combination of anionic ring-opening polymerization and postmodification with functional vinyl compounds.