Dual-Functional Antifogging/Antimicrobial Polymer Coating

A transparent p-coumaric acid-grafted-chitosan coating with antimicrobial, antioxidant and antifogging properties for fruit packaging applications

The study aimed to develop a novel, transparent and non-toxic coating with antimicrobial, antioxidant, and antifogging properties. The p-coumaric acid-grafted chitosan (CS-PCA) was synthesized via a carbodiimide coupling reaction and then characterized. The CS-PCA coatings were further prepared using the casting method. The CS-PCA coatings obtained exhibited excellent transparency, UV-light barrier ability, and antifogging properties, as confirmed by spectroscopy and antifogging tests. The CS-PCA coatings showed stronger antioxidant capacity and antimicrobial properties against Escherichia coli, Staphylococcus aureus and Botrytis cinerea compared to CS. The multifunctional coatings were further coated on the polyethylene cling film and their effectiveness was confirmed through a strawberry preservation test. The decay of the strawberries was reduced by CS-PCA coated film at room temperature.

Si-doped carbonized polymer dot as robust hydrophilic coating using for high efficiency antifogging

Hydrophilic coating can prevent surface from fogging but its application is limited by low mechanical performance. In this study, a hydrophilic coating was prepared by crosslinking the Si-doped carbonized polymer dot (Si-CPD) with 3-glycidyloxypropyltrimethoxysilane (GPTMS) and ethylene oxide (EO). The hydrophilic coating can be used as robust hydrophilic anti-fogging coating. The Si-CPD derived from ethylene diamine tetraacetic acid (EDTA) and aminopropyl oligosiloxanes (APOS) was successfully prepared via one-step hydrothermal method. Then, a resin solution was prepared by mixing Si-CPD, GPTMS and EO. Epoxy group of GPTMS and EO can react with amino group of Si-CPD. Finally, a composite coating with antifogging function can be obtained by simple heating curing. Due to the introduction of hydroxyl which derived from EO, the coating shows excellent antifogging performance. Meanwhile, the presence of inorganic component endows the coating with outstanding mechanical performance. The coating has great potential in related applications, such as optical lenses, mirrors and other transparency substrates.

Topochemistry for Difficult Peptide-Polymer Synthesis: Single-Crystal-to-Single-Crystal Synthesis of an Isoleucine-Based Polymer, a Hydrophobic Coating Material

Polymers of hydrophobic amino acids are predicted to be potential coating materials for the creation of hydrophobic surfaces. The oligopeptides of hydrophobic amino acids are called "difficult peptides"; as the name suggests, it is difficult to synthesize them by conventional methods. We circumvented this synthetic challenge by adopting topochemical azide-alkyne cycloaddition (TAAC) polymerization of a hydrophobic dipeptide monomer. We designed an Ile-based dipeptide, decorated with azide and alkyne, which arrange in the crystal in a head-to-tail fashion with the azide and alkyne of the adjacent molecules in a ready-to-react orientation. The monomer, on mild heating of its crystals, undergoes regiospecific TAAC polymerization to yield a 1,4-disubstituted-triazole-linked polymer in a single-crystal-to-single-crystal fashion. The solid obtained after evaporation of the monomer solution also maintained crystallinity and underwent regiospecific topochemical polymerization as in the case of crystals. This topochemical polymerization could be studied using different techniques such as FTIR, NMR, DSC, GPC, MALDI, PXRD, and SCXRD. Since the polymer is insoluble in common solvents and hence difficult to coat surfaces, the monomer was first sprayed and evaporated on various surfaces and polymerized on the surface. Such polymer-coated surfaces exhibited water contact angles of up to 134°, showing that this Ile-derived polymer is very hydrophobic and can potentially be used as a coating material for various applications.

Radiation polymerization for the preparation of universal coatings: remarkable anti-fogging and frost-resisting performance

Hydrophilic anti-fogging coatings have attracted considerable attention due to their ease of preparation and excellent fog resistance. In this study, a hydrophilic anti-fogging coating based on the random copolymer p(AA-co-SAS) was prepared using acrylic acid (AA) and sodium allylsulfonate (SAS) as monomers through radiation polymerization. The introduction of SAS successfully transformed the random copolymer from a gel state into a film-forming polymer solution. The presence of AA structural units in p(AA-co-SAS) improved the film-forming properties of the polymer solution. Additionally, there was a positive correlation between the proportion of SAS structural units in the random copolymer and the scratch hardness and wetting properties of the coating. After coating polycarbonate (PC) sheets, the surface hydrophilicity was significantly enhanced, with the contact angle of PC-AA10/SAS5 decreasing from 100.1° to 18.8° within 50 seconds. The outstanding wetting properties endowed the coating with exceptional anti-fogging and frost-resisting performance. It exhibited optimal transparency under both testing conditions and demonstrated good stability during cyclic testing. Tape adhesion tests indicated that the adhesion between the coating and PC reached a 5B level. When AA10/SAS5 was applied to PET film, glass, and PMMA goggles, all samples showed excellent anti-fog performance. Even after being naturally placed for one year under ambient conditions, the PMMA goggles still maintained good performance in the anti-fog and frost resistance tests. The remarkable comprehensive properties of the polymer coating based on p(AA-co-SAS) suggest enormous potential applications in industries such as packaging, healthcare, and optical equipment.

Chitosan-based films blended with moringa leaves and MgO nanoparticles for application in active food packaging

This study aims to address the issue of environmental pollution caused by non-biodegradable petroleum-based food packaging by exploring the application of biodegradable films. Film casting was employed to fabricate food packaging films from chitosan (CS) and polyvinyl alcohol (PVA) polymers blended with moringa extract (MoE) and various concentrations of magnesium oxide nanoparticles (MgO NPs). The films were characterized through multiple techniques, including UV spectroscopy, Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), and Fourier-transform Infrared Spectroscopy (FTIR). The study investigated the physicomechanical properties, water solubility, water vapor transmission rate, oxygen permeability, migration test, biodegradability, contact angle, anti-fogging, antibacterial and antifungal activity, and application of the films for food packaging. The results showed that blending CS/PVA films with MoE and MgO NPs significantly improved their mechanical properties. The highest tensile strength of 98 MPa was observed in the CPMMgO-0.5 film. The solubility of the films was low, with CPMMgO-0 and CPMMgO-0.25 demonstrating the lowest solubility as weight decreased by 3.41 % and 3.47 %, respectively. The water vapor transmission rate and oxygen permeability decreased with increasing MgO NP concentrations, with the CPMMgO-0.5 film exhibiting the lowest values. The films also demonstrated good biodegradability, anti-fogging ability, antibacterial and antifungal activity, and low water solubility, enabling bead encapsulation over 14 days in good condition. Moreover, the thermal stability of the films was improved, extending the shelf life of bread. Therefore, the fabricated films provide a promising alternative to non-degradable plastic packaging, which heavily contributes to environmental pollution.

Antimicrobial films fabricated with myricetin nanoparticles and chitosan derivation microgels for killing pathogenic bacteria in drinking water

Pathogenic bacteria in drinking water threaten human health and life. In the work, antimicrobial films composed of myricetin@tannic acid (My@TA) nanoparticles (NPs) and chitosan derivation microgels were developed to kill pathogenic bacteria in drinking water. Hydrophobic My was first made into water soluble My@TA NPs using a solvent exchange method with TA as stabilizer. Polymeric microgels of carboxymethyl chitosan (CMCS)/hydroxypropyltrimethyl ammonium chloride chitosan (HACC) were then fabricated with a blending method. CMCS&HACC/My@TA multilayer films were further deposited on the internal surface of PET bottles by using a layer-by-layer (LbL) assembly technique. The PET bottles coated with the films could effectively kill pathogenic bacteria in water such as S. aureus, E. coli, Staphylococcus epidermidis, Pseudomonas fluorescens, Listeria monocytogenes and methicillin resistant Staphylococcus aureus (MRSA). In addition, CMCS&HACC/My@TA films displayed good antioxidant activity, water resistance, and in vivo biocompatibility with heart, liver, spleen, lung and kidney organs. We believe that the container coated with CMCS&HACC/My@TA films can be applied to prevent microbial contamination of drinking water.

Structurally Heterogeneous Amphiphilic Conetworks of Poly(vinyl imidazole) Derivatives with Potent Antimicrobial Properties and Cytocompatibility

We report the construction of amphiphilic conetwork (APCN)-based surfaces with potent antimicrobial activity and biofilm inhibition ability. The construction strategy is based on the separation of lipophilic alkyl groups (>C6) from the cationic network to obtain good antibacterial properties. The reaction of partially alkylated poly(vinyl imidazole) with the activated halide compounds followed by coating a glass or poly(dimethylsiloxane) (PDMS) sheet leads to the formation of the APCN surface. The dangling alkyl chains, crosslinking junctions, and unreacted vinyl imidazole groups are heterogeneously distributed in the APCNs. The swelling, mechanical property, and phase morphology of the APCN films have been evaluated. Bacterial cell disrupting potency of the APCN coatings increases with increasing alkyl chain length from C6 to C18 with somewhat more of an effect on Escherichia coli as compared to Bacillus subtilis bacteria. The minimum inhibitory amount of the APCNs on glass and a hydrophobic PDMS surface is in the range of 0.02-0.04 mg/cm2 depending on the chain length of the alkyl and the degree of quaternization. The effect of the type of crosslinker for the construction of the conetwork on the antimicrobial property has been evaluated to elucidate the exclusive design of the APCNs. The APCN-based coatings provide potent biocidal activity without much negatively affecting the hemocompatibility and cytocompatibility. These APCNs provide a good model system for comparative evaluation of the biocidal property and structural effect on the biocidal activity.

A Facile Strategy to Construct Anti-Swelling, Antibacterial, and Antifogging Coatings for Protection of Medical Goggles

During the COVID-19 (Corona Virus Disease 2019) pandemic, traditional medical goggles are not only easy to attach bacteria and viruses in long-term exposure, but easy to fogged up, which increases the risk of infection and affects productivity. Bacterial adhesion and fog can be significantly inhibited through the hydrogel coatings, owing to super hydrophilic properties. On the one hand, hydrogel coatings are easy to absorb water and swell in wet environment, resulting in reduced mechanical properties, even peeling off. On the other hand, the hydrogel coatings don't have intrinsic antibacterial properties, which still poses a potential risk of bacterial transmission. Herein, an anti-swelling and antibacterial hydrogel coating is synthesized by 2-hydroxyethyl methacrylate (HEMA), acrylamide (AM), dimethylaminoethyl acrylate bromoethane (IL-Br), and poly(sodium-p-styrenesulfonate) (PSS). Due to the self-driven entropy reduction effect of polycation and polyanion, an ion cross-linking network is formed, which endows the hydrogel coating with excellent antiswelling performance. Moreover, because of the synergistic effect of highly hydrated surfaces and the active bactericidal effect from quaternary ammonium cations, the hydrogel coating exhibits outstanding antifouling performances. This work develops a facile strategy to fabricate anti-swelling, antifouling, and antifogging hydrogel coatings for the protection of medical goggles, and also for biomedical and marine antifouling fields.

An Overview of Polymer Composite Films for Antibacterial Display Coatings and Sensor Applications

The escalating presence of pathogenic microbes has spurred a heightened interest in antimicrobial polymer composites tailored for hygiene applications. These innovative composites ingeniously incorporate potent antimicrobial agents such as metals, metal oxides, and carbon derivatives. This integration equips them with the unique ability to offer robust and persistent protection against a diverse array of pathogens. By effectively countering the challenges posed by microbial contamination, these pioneering composites hold the potential to create safer environments and contribute to the advancement of public health on a substantial scale. This review discusses the recent progress of antibacterial polymer composite films with the inclusion of metals, metal oxides, and carbon derivatives, highlighting their antimicrobial activity against various pathogenic microorganisms. Furthermore, the review summarizes the recent developments in antibacterial polymer composites for display coatings, sensors, and multifunctional applications. Through a comprehensive examination of various research studies, this review aims to provide valuable insights into the design, performance, and real-time applications of these smart antimicrobial coatings for interactive devices, thus enhancing their overall user experience and safety. It concludes with an outlook on the future perspectives and challenges of antimicrobial polymer composites and their potential applications across diverse fields.

Recent advances in prevailing antifogging surfaces: structures, materials, durability, and beyond

In past decades, antifogging surfaces have drawn more and more attention owing to their promising and wide applications such as in aerospace, traffic transportation, optical devices, the food industry, and medical and other fields. Therefore, the potential hazards caused by fogging need to be solved urgently. At present, the up-and-coming antifogging surfaces have been developing swiftly, and can effectively achieve antifogging effects primarily by preventing fog formation and rapid defogging. This review analyzes and summarizes current progress in antifogging surfaces. Firstly, some bionic and typical antifogging structures are described in detail. Then, the antifogging materials explored thus far, mainly focusing on substrates and coatings, are extensively introduced. After that, the solutions for improving the durability of antifogging surfaces are explicitly classified in four aspects. Finally, the remaining big challenges and future development trends of the ascendant antifogging surfaces are also presented.

Multifunctional Layer-by-Layer Coating Based on a New Amphiphilic Block Copolymer via RAFT-Mediated Polymerization-Induced Self-Assembly Process

In this hi-tech world, the "smart coatings" have sparked significant attention among materials scientists because of their versatile applications. Various strategies have been developed to generate smart coatings in the past 2 decades. The layer-by-layer (LbL) technique is the most commonly employed strategy to produce a smart coating for suitable applications. Here, we present a smart coating with healing, antifogging, and fluorescence properties fabricated by the LbL assembly of an anionic amphiphilic block copolymer latex and cationic inorganic POSS (polyhedral-oligomeric-silsesquioxane) nanoparticles. In this case, a new anionic block copolymer (BCP), {poly(sodium styrene sulfonate)-block-poly[2-(acetoacetoxy)ethyl methacrylate]}, (PSS-b-PAAEMA) was synthesized via surfactant-free RAFT-mediated emulsion polymerization using the PISA technique. The PSS-b-PAAEMA was characterized by ¹H NMR, dynamic light scattering, scanning electron microscopy, and transmission electron microscopy analyses as well as by UV-vis and photoluminescence spectroscopy. For LbL coating fabrication, an amine-modified glass was successively dipped in the anionic latex and cationic POSS solution. The transparent coating exhibited good fluorescence properties under UV light (blue color). The antifogging performance of the coating was also investigated using both cold-warm and hot-vapor techniques. Additionally, the coating surface showed a significant healing activity with a healing efficiency of >75% through ionic interaction. Thus, this finding provides a simple low volatile organic compound (VOC) water-based LbL coating with multifunctional properties that can be a potential material for versatile applications.

Catheters with Dual-Antimicrobial Properties by Gamma Radiation-Induced Grafting

Dual antimicrobial materials that have a combination of antimicrobial and antifouling properties were developed. They were developed through modification using gamma radiation of poly (vinyl chloride) (PVC) catheters with 4-vinyl pyridine (4VP) and subsequent functionalization with 1,3-propane sultone (PS). These materials were characterized by infrared spectroscopy, thermogravimetric analysis, swelling tests, and contact angle to determine their surface characteristics. In addition, the capacity of the materials to deliver ciprofloxacin, inhibit bacterial growth, decrease bacterial and protein adhesion, and stimulate cell growth were evaluated. These materials have potential applications in the manufacturing of medical devices with antimicrobial properties, which can reinforce prophylactic potential or even help treat infections, through localized delivery systems for antibiotics.

Combined antifogging and antireflective double nanostructured coatings for LiDAR applications

To increase the performance of optical systems, a good antireflective coating is required to ensure low reflectance and high transmittance of optical surfaces. Further problems, such as fogging that causes light scattering, negatively affect the image quality. This implies that other functional properties are also required. Presented here is a highly promising combination of an antireflective double nanostructure on top of an antifog coating with long-term stable properties, generated in a commercial plasma-ion-assisted coating chamber. It is demonstrated that the nanostructures do not affect the antifog properties and can be successfully used for many applications.

Long-Term Antifogging Coating Based on Black Phosphorus Hybrid Super-Hydrophilic Polymer Hetero-Network

The antifogging coating based on super-hydrophilic polymer is regarded as the most promising strategy to avoid fogging but suffers from short-term effectiveness due to antifogging failure induced by water invasion. In this study, a black phosphorus nanosheets (BPs) hybrid polymer hetero-network coating (PUA/PAHS/BPs HN) was prepared by UV curing for the first time to achieve long-term antifogging performance. The polymer hetero-network (HN) structure was composed of two novel cross-linked acrylic resin and polyurethane acrylate. Different from physical blending, a covalent P-C bond between BPs and polymer is generated by UV initiated free radical reaction, resulting in BPs firmly embedded in the polymer HN structure. The BPs enriched on the coating surface by UV regulating migration prevent permeation of water towards the inside of the coating through its own good water-based lubricity and water absorption capacity. Compared with the nonhybrid polymer HN, PUA/PAHS/BPs HN not only has higher hardness and better friction resistance properties, but also exhibits superior water resistance and longer antifogging duration. Since water invasion was greatly reduced by BPs, the PUA/PAHS/BPs HN coating maintained antifogging duration for 60 min under a 60 °C water vapor test and still maintained long-term antifogging performance after being immersed in water for 5 days.

Methyl Methacrylate-Based Copolymers: Recent Developments in the Areas of Transparent and Stretchable Active Matrices

The recent advancements of poly(methyl methacrylate) (PMMA) as a transparent flexible polymer material have been utilized in numerous areas of engineering and materials science. PMMA-based copolymers demonstrate outstanding mechanical and optical properties owing to high transparency, lightweight nature, high impact resistance, and stress relaxation across glass transition temperature. These copolymers have unique characteristics of retaining optical and microstructural integrities during successive bending or elongations which make them an attractive choice for materials of stretchable electronics. In particular, there has been an escalated rise in the use of methyl methacrylate (MMA)-based transparent and stretchable copolymer films during the recent decades. Therefore, we have highlighted these recent developments into a comprehensive review in order to aid the future progress in these diverse fields. Herein, we have highlighted the scope of MMA as an important building block for the synthesis of highly transparent and flexible materials. The synthetic pathways of these copolymer materials and the resulting mechanical properties have been discussed. Moreover, the immense scope of these copolymer films has been highlighted by virtue of their applications in various industries.

Bifunctional Amphiphilic Nanospikes with Antifogging and Antibiofouling Properties

Over the past few decades, extensive research efforts have been devoted to developing surfaces with unique functionalities, such as controlled wettability, antibiofouling, antifogging, and anti-icing behavior, for applications in a wide range of fields, including biomedical devices, optical instruments, microfluidics, and energy conservation and harvesting. However, many of the previously reported approaches have limitations with regard to eco-friendliness, multifunctionality, long-term stability and efficacy, and cost effectiveness. Herein, we propose a scalable bifunctional surface that simultaneously exhibits excellent antifogging and antibiofouling properties based on the synergistic integration of an eco-friendly and bio-friendly polyethylene glycol (PEG) hydrogel, oleamide (OA), and nanoscale architectures in a single flexible platform. We demonstrate that the PEG-OA-nanostructure hybrid exhibits excellent antifogging performance owing to its enhanced water absorption and spreading properties. We further show that the triple hybrid exhibits notable biofilm resistance without the use of toxic biocides or chemicals by integrating the "fouling-resistant" mechanism of the PEG hydrogel, the "fouling-release" mechanism of OA, and the "foulant-killing" mechanism of the nanostructures.

Transparent Composite Films Showing Durable Antifogging and Repeatable Self-Healing Properties Based on an Integral Blend Method

Antifogging coatings for infrastructures and transparent objects have attracted much attention lately from the perspective of safety and visibility. We have developed a one-pot process to fabricate transparent composite films showing long-lasting antifogging and fast repeatable self-healing properties based on an integral blend (IB) method. This method does not require any specific pretreatments of inorganic fillers/particles. Thus, the precursor solutions could be prepared in a single step by simply mixing raw materials, e.g., poly(vinylpyrrolidone) (PVP) having different molecular weights (MWs: 55, 360, and 1300 k), nano-clay particles (NCPs), and amino-terminated organosilane (AOS). In this study, to control the degree of cross-linking between the PVP matrices and NCPs, addition of AOS as a cross-linker to the PVP matrices (weight percentage of AOS to the PVP matrices, α = 0.01-300%) was carefully controlled. Transparency and self-healing abilities/kinetics of the resulting samples were found to be strongly influenced by both the MWs of PVP and α values. Samples spin-coated with the lowest M_W of PVP (55 k) and α values of 0.01-1% gave highly transparent and durable antifogging performance. For example, no fogging was observed for 7 days under >80% relative humidity, and scratches about 30 μm in width could be completely self-healed within a few hours. However, samples with α > 10% gave opaque/grayish films that did not show any self-healing abilities because of an increase in cross-linking of the matrices. The optimized precursor solution was also deposited directly onto the glass slides covered with a transparent porous silica nano-framework (SNF) by a spray-coating method. Due to the formation of the hard and superhydrophilic/hygroscopic SNF with a large surface area, durability of antifogging and self-healing properties of the composite films were moderately improved, compared to those on the flat glass slides.

Fabrication of Transparent Silica/PEG Smooth Thin Coatings on Polymeric Films for Antifogging Applications

Fog accumulation on surfaces typically has a negative effect by reducing their transparency and efficiency. Applications such as plastic packaging, agricultural films, and particularly many optical devices suffer from these negative effects. One way to prevent fogging is to coat the substrate with an antifogging coating having a smooth surface and hydrophilic surface chemical groups. This causes the fog water droplets that come into contact with the substrate to completely flatten across its surface, thus retaining transparency. These coatings are mostly relegated to laboratory research due to their insufficient stability and costly synthetic processes. We proposed the use of organically modified silica particles consisting of a mixture of tetraethyl orthosilicate and methacryloxypropyltriethoxysilane, which were grown in situ in the presence of a corona-activated polyethylene film, thus providing a thin siloxane coating containing activated double bonds. An additional coating of poly(ethylene glycol) diacrylate was then spread on the coated film and polymerized via UV curing. The in situ process and UV curing anchored the coating to the substrate through covalent bonds, which provided additional stability. This coating exhibited low surface roughness and contact angle, which resulted in excellent antifogging properties when exposed to a hot-fog test. Furthermore, the antifogging coating retained its properties after 10 hot-fog cycles, indicating the high coating stability. Additionally, the coating was found durable to immersion in aqueous pH levels 1-13 and detergent solutions as well as to tape test applications and sand test. This coating was compared to a commercially available antifogging spray, which was used to coat a polyethylene film. This resulted in excellent initial antifogging properties, which decreased after exposure to durability tests. The results of the in situ coating process indicate its potential uses for industrial applications.

Phase Separation of Aqueous Poly(diisopropylaminoethyl methacrylate) upon Heating

Poly(diisopropylaminoethyl methacrylate) (PDPA) is a pH- and thermally responsive water-soluble polymer. This study deepens the understanding of its phase separation behavior upon heating. Phase separation upon heating was investigated in salt solutions of varying pH and ionic strength. The effect of the counterion on the phase transition upon heating is clearly demonstrated for chloride-, phosphate-, and citrate-anions. Phase separation did not occur in pure water. The buffer solutions exhibited similar cloud points, but phase separation occurred in different pH ranges and with different mechanisms. The solution behavior of a block copolymer comprising poly(dimethylaminoethyl methacrylate) (PDMAEMA) and PDPA was investigated. Since the PDMAEMA and PDPA blocks phase separate within different pH- and temperature ranges, the block copolymer forms micelle-like structures at high temperature or pH.

Effective Antifogging Coating from Hydrophilic/Hydrophobic Polymer Heteronetwork

Fogging on optical devices may severely impair vision, resulting in unacceptable adverse consequences. Hydrophilic coatings can prevent surface fogging by instantly facilitating pseudo-film water condensation but suffer from short antifogging duration due to water film thickening with further condensation. Here, an innovative strategy is reported to achieve longer antifogging duration via thickening the robust bonded hydrophilic/hydrophobic polymer heteronetwork coating to enhance its water absorption capacity. The combination of strong interfacial adhesion and hydrophilic/hydrophobic heteronetwork structure is key to this approach, which avoids interfacial failure and swelling-induced wrinkles under typical fogging conditions. The developed antifogging coating exhibits prolonged antifogging durations over a wide temperature range for repetitious usages. Eyeglasses coated with this coating successfully maintained fog-free vision in two typical scenarios. Besides, the coating recipes developed in this study also have potential as underwater glues as they demonstrate strong adhesions to both glass and polymer substrates in wet conditions.

"Brush-like" Amphiphilic Polymer for Environmental Adaptive Coating

Multiple functional coating is urgently needed in complex service surroundings to meet various requirements. In this work, a brush-like amphiphilic copolymer of poly methacryloxyethyl dimethyl butyl ammonium bromide-polydimethylsiloxane (pMDBAB-PDMS) was synthesized to construct an environment-adaptive multifunctional coating based on the copolymer via the UV-curing method. The special molecule chains of the copolymer assembled predominately on the coating surface in different surroundings, which rendered the surface with various functions. In water-rich surroundings, the hydrophilic quaternary ammonium groups in the coating endow the coating surface with antifogging, oleophobicity underwater, self-cleaning, antibacteria, triboelectric resistance, and super lubrication properties. In dry air surroundings, the long, flexible, low surface energy molecular PDMS chains tend to distribute on the top of the coating surface, which gives a low friction coefficient and antioil properties. This work presents a strategy to construct environmental adaptive coating that has an important application prospect in the field of optical lens.

Biocompatible mechano-bactericidal nanopatterned surfaces with salt-responsive bacterial release

Bio-inspired nanostructures have demonstrated highly efficient mechano-bactericidal performances with no risk of bacterial resistance; however, they are prone to become contaminated with the killed bacterial debris. Herein, a biocompatible mechano-bactericidal nanopatterned surface with salt-responsive bacterial releasing behavior is developed by grafting salt-responsive polyzwitterionic (polyDVBAPS) brushes on a bio-inspired nanopattern surface. Benefiting from the salt-triggered configuration change of the grafted polymer brushes, this dual-functional surface shows high mechano-bactericidal efficiency in water (low ionic strength condition), while the dead bacterial residuals can be easily lifted by the extended polymer chains and removed from the surface in 1 M NaCl solution (high ionic strength conditions). Notably, this functionalized nanopatterned surface shows selective biocidal activity between bacterial cells sand eukaryotic cells. The biocompatibility with red blood cells (RBCs) and mammalian cells was tested in vitro. The histocompatibility and prevention of perioperative contamination activity were verified by in vivo evaluation in a rat subcutaneous implant model. This nanopatterned surface with bacterial killing and releasing activities may open new avenues for designing bio-inspired mechano-bactericidal platforms with long-term efficacy, thus presenting a facile alternative in combating perioperative-related bacterial infection. STATEMENT OF SIGNIFICANCE: Bioinspired nanostructured surfaces with noticeable mechano-bactericidal activity showed great potential in moderating drug-resistance. However, the nanopatterned surfaces are prone to be contaminated by the killed bacterial debris and compromised the bactericidal performance. In this study, we provide a dual-functional antibacterial conception with both mechano-bactericidal and bacterial releasing performances not requiring external chemical bactericidal agents. Additionally, this functionalized antibacterial surface also shows selective biocidal activity between bacteria and eukaryotic cells, and the excellent biocompatibility was tested in vitro and in vivo. The new concept for the functionalized mechano-bactericidal surface here illustrated presents a facile antibiotic-free alternative in combating perioperative related bacterial infection in practical application.

Antimicrobial Properties of the Triclosan-Loaded Polymeric Composite Based on Unsaturated Polyester Resin: Synthesis, Characterization and Activity

The manufacturing of sanitary and household furniture on a large scale with inherently antimicrobial properties is an essential field of research. This work focuses on the synthesis of polymer composites based on the unsaturated polyester of resin loaded with 5 wt.%-Triclosan produced by a co-mixing approach on automated technological complex with a potential for broad applications. According to findings, the polymer composite has a non-porous structure (surface area < 1.97 m²/g) suitable for sanitary applications to reduce the growth of bacteria. The chemical composition confirmed the presence of major elements, and the inclusion of Triclosan was quantitatively confirmed by the appearance of chlorine on XRF (1.67 wt.%) and EDS (1.62 wt.%) analysis. Thermal analysis showed the difference of 5 wt.% in weight loss, which confirms the loading of Triclosan into the polymer matrix. The polymer composite completely inhibited the strains of S. aureus 6538-P, S. aureus 39, S. epidermidis 12228, and Kl. Pneumoniae 10031 after 5-min contact time. The antimicrobial effects against Kl. pneumoniae 700603, Ps. aeruginosa 9027 and Ps. aeruginosa TA2 strains were 92.7%, 85.8% and 18.4%, respectively. The inhibition activity against C. albicans 10231 and C. albicans 2091 was 1.6% and 82.4%, respectively; while the clinical strain of C. albicans was inhibited by 92.2%. The polymer composite loaded with 5 wt.%-Triclosan displayed a stability over the period that illustrates the possibility of washing the composite surface.

Hyperbranched Polyesters Based on Indole- and Lignin-Derived Monomeric Aromatic Aldehydes as Effective Nonionic Antimicrobial Coatings with Excellent Biocompatibility

This research aims to investigate nonionic hyperbranched polyesters (HBPs) derived from indole and lignin resources as new nontoxic antimicrobial coatings. Three nonionic HBPs with zero to two methoxy ether substituents on each benzene ring in the polymer backbones were synthesized by melt-polycondensation of three corresponding AB2 monomers. The molecular structures and thermal properties of the obtained HBPs were characterized by gel permeation chromatography, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry analyses. These HBPs were conveniently spin-coated on a silicon substrate, which exhibited significant antibacterial effect against Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis). The presence of methoxy substituents enhanced the antimicrobial effect, and the resulting polymers showed negligible leakage in water. Finally, the polymers with the methoxy functionality exhibited excellent biocompatibility according to the results of hemolysis and MTT assay, which may facilitate their biomedical applications.

Advances in emerging technologies for the decontamination of the food contact surfaces

Foodborne pathogens could be transferred to food from food contact surfaces contaminated by poor hygiene or biofilm formation. The food processing industry has various conditions favouring microbes' adherence, such as moisture, nutrients, and the microbial inoculums obtained from the raw material. The function of the ideal antimicrobial surface is preventing initial attachment of the microbes, killing the microbes or/and removing the dead bacteria. This review article provides detail about the challenges food industries are facing with respect to food contact materials. It also summarises the merits and demerits of several sanitizing methods developed for industrial use. Furthermore, it reviews the new and emerging techniques that enhance the efficiency of reducing microbial contamination. Techniques such as surface functionalisation, high-intensity ultrasound, cold plasma technologies etc. which have high potential to be used for the decontamination of food contact surfaces are discussed. The emerging designs of antibacterial surfaces provide the opportunity to reduce or eradicate the adhesion of microorganisms. The most important purpose of these surfaces is to prevent the attachment of bacteria and to kill the bacteria that come in contact. These emerging technologies have a high potential for developing safe and inert food contact materials for the food industry.

One-step zwitterionization and quaternization of thick PDMAEMA layer grafted through subsurface-initiated ATRP for robust antibiofouling and antibacterial coating on PDMS

In this work, we demonstrate the grafting of thick poly((2-dimethylamino) ethyl methacrylate) (PDMAEMA) layer on PDMS via subsurface-initiated atom transfer radical polymerization (SSI-ATRP). The self-migration of DMAEMA monomers into the subsurface of PDMS is proven to be the dominant factor for the success of SSI-ATRP. The as-prepared thick microscale graft layer on PDMS shows much better abrasion resistance than nanoscale graft layer obtained by conventional surface-initiated atom transfer radical polymerization (SI-ATRP) under identical condition. Taking advantage of the tertiary amines of PDMAEMA, the simultaneous zwitterionization and quaternization of the PDMAEMA thick layer is realized through a facile one-step process. The effect of zwitterionization and quaternization degree on the antibiofouling and antibacterial properties is investigated. The results show that a relatively high zwitterionization degree (75 mol%) and a low quaternization degree (25 mol%) exhibit a good well-balanced effect on both fouling repellence and bactericidal activity. This work may lead to the development of robust bifunctional antibiofouling and antibacterial surfaces via SSI-ATRP strategy.

Antimicrobial coatings for environmental surfaces in hospitals: a potential new pillar for prevention strategies in hygiene

Recent reports provide evidence that contaminated healthcare environments represent major sources for the acquisition and transmission of pathogens. Antimicrobial coatings (AMC) may permanently and autonomously reduce the contamination of such environmental surfaces complementing standard hygiene procedures. This review provides an overview of the current status of AMC and the demands to enable a rational application of AMC in health care settings. Firstly, a suitable laboratory test norm is required that adequately quantifies the efficacy of AMC. In particular, the frequently used wet testing (e.g. ISO 22196) must be replaced by testing under realistic, dry surface conditions. Secondly, field studies should be mandatory to provide evidence for antimicrobial efficacy under real-life conditions. The antimicrobial efficacy should be correlated to the rate of nosocomial transmission at least. Thirdly, the respective AMC technology should not add additional bacterial resistance development induced by the biocidal agents and co- or cross-resistance with antibiotic substances. Lastly, the biocidal substances used in AMC should be safe for humans and the environment. These measures should help to achieve a broader acceptance for AMC in healthcare settings and beyond. Technologies like the photodynamic approach already fulfil most of these AMC requirements.

Dual functional coatings with antifogging and antimicrobial performances for endoscope lens, via facile adsorption-cross-linking strategy

Surface fogging causes various inconvenience for human daily life, especially for clinic inspection and medical diagnosis, hence the surfaces with reliable antifogging performances have received tremendous interests. Herein, through a facile adsorption-cross-linking strategy, a dual functional coating with both excellent antifogging/frost-resisting properties and reliable antibacterial activity has been steadily integrated onto varied substrates. A series of copolymers poly(HEAA-co-QAC-co-BP) with UV-initiable BP groups are synthesized, and then are covalently fixed on the substrate surfaces via UV triggered cross-linking reaction. The hydrophilic HEAA units endow the surface with excellent antifogging performance, while the introduced QAC groups bring essential antibacterial activity. ZOI results prove that the antibacterial activity stems from the surface contact-killing of bacteria, without releasing any bactericidal agents. Moreover, the functional surface exhibits remarkable resistance toward non-specific protein adsorption as well as no obvious effect on the hemolysis. The coating with the unique merits of both antifogging and antibacterial properties could find broad applications in antifogging fields, in particular for medical diagnosis, health monitoring, etc.

Bioinspired adhesive coatings from polyethylenimine and tannic acid complexes exhibiting antifogging, self-cleaning, and antibacterial capabilities

In this work, we develop a simple yet robust method to fabricate a bioinspired adhesive coating based on polyethyleneimine (PEI) and tannic acid (TA) complexes, exhibiting excellent antifogging, self-cleaning, and antibacterial properties. The polyethyleneimine-tannic acid (PEI-TA) complexes coating combined with the bioinspired adhesive property from TA can be effectively and stably coated onto various substrates through a one-step deposition process, and the hydrophilicity of the coated substrates can be significantly enhanced with their water contact angle less than 10°. The bioinspired adhesive coating endows the coated substrates with outstanding antifogging and self-cleaning performance. Moreover, it is found that the PEI-TA coated safety goggles display excellent durability and antifogging capability compared to the commercial antifogging safety goggles and commercial antifogging agents coated safety goggles under 65 ℃ vapor condition for 2 h. Furthermore, the PEI-TA coatings show superior antibacterial activities for Gram-negative Escherichiak coli and Gram-positive Staphylococcus aureus. The antifogging, self-cleaning, and antibacterial coating provides widely potential application prospects in optical and medical devices.

Antimicrobial Polymeric Structures Assembled on Surfaces

Pathogenic microbes are the main cause of various undesired infections in living organisms, including humans. Most of these infections are favored in hospital environments where humans are being treated with antibiotics and where some microbes succeed in developing resistance to such drugs. As a consequence, our society is currently researching for alternative, yet more efficient antimicrobial solutions. Certain natural and synthetic polymers are versatile materials that have already proved themselves to be highly suitable for the development of the next-generation of antimicrobial systems that can efficiently prevent and kill microbes in various environments. Here, we discuss the latest developments of polymeric structures, exhibiting (reinforced) antimicrobial attributes that can be assembled on surfaces and coatings either from synthetic polymers displaying antiadhesive and/or antimicrobial properties or from blends and nanocomposites based on such polymers.

Facile multifunctional-mode of fabricated biocompatible human serum albumin/reduced graphene oxide/Cladophora glomeratananoparticles for bacteriostatic phototherapy, bacterial tracking and antioxidant potential

To overcome multi-drug resistance in microbes, highly efficient antimicrobial substances are required that have a controllable antibacterial effect and are biocompatible. In the present study, an efficient phototherapeutic antibacterial agent, human serum albumin (HSA)/reduced graphene oxide (rGO)/Cladophora glomeratabionanocomposite was synthesized by the incorporation of rGO nanoparticles with HSA, forming protein-rGO, and decorated with a natural freshwater seaweedCladophora glomerata. The prepared HSA/rGO/Cladophora glomeratabionanocomposite was characterized by spectroscopic (UV-vis, FTIR, XRD and Raman) and microscopic (TEM and SEM) techniques. The as-synthesized bionanocomposite showed that sunlight/NIR irradiation stimulated ROS-generating dual-phototherapic effects against antibiotic-resistant bacteria. The bionanocomposite exerted strong antibacterial effects (above 96 %) against amoxicillin-resistantP. aeruginosaandS. aureus, in contrast to single-model-phototherapy. The bionanocomposite not only generated abundant ROS for killing bacteria, but also expressed a fluorescence image for bacterial tracking under sunlight/NIR irradiation. Additionally, the bionanocomposite displayed pronounced antioxidant activity.

Robust and Antiswelling Hollow Hydrogel Tube with Antibacterial and Antithrombotic Ability for Emergency Vascular Replacement

Infection and thrombosis are the two major complications in almost any indwelling intravascular catheters, leading to adverse consequences. Here, we report a robust and antiswelling hollow hydrogel tube that is prepared by copolymerizing a hydrogen-bonding (H-bonding) monomer and a zinc methacrylate (ZMA) monomer in the absence of any chemical cross-linker. The strong H-bonding interactions from the side chain of N-acryloylsemicarbazide (NASC) endow the hydrogel with high mechanical strength and swelling stability. Introduction of ZMA affords a superhydrophilic surface, and the release of a zinc ion (Zn²⁺) from the hydrogel can kill nearly 100% both of Staphylococcus aureus and Escherichia coli, indicating its excellent antibacterial ability. Importantly, the P(NASC-co-ZMA) hydrogel exhibits better antithrombosis ability due to the resistant adhesion of fibrinogen protein and platelets, as well binding calcium ions (Ca²⁺) from the blood. The hydrogel tube is used to connect the ex vivo arteriovenous shunt circuit or implanted into the left carotid artery in the rabbit model, showing a better patency rate. All of these results suggest that this hydrogel tube may mitigate infection and thrombosis complications, thus holding potential as an artificial blood vessel for emergency vascular replacement.

Highly Transparent, Robust Hydrophobic, and Amphiphilic Organic-Inorganic Hybrid Coatings for Antifogging and Antibacterial Applications

The control of surface wettability through a combination of surface roughness, chemical composition, and structural modification has attracted significant attention for antifogging and antibacterial applications. Herein, a two-step spin-coating method for amphiphilic organic-inorganic hybrid materials with incorporated transition metal ions is presented. The coating solution was prepared via photochemical thiol-ene click reaction between the mercapto functional group in trimethylolpropane tris(3-mercaptopropionate) and the vinyl functionalized silica precursor 3-(trimethoxysilyl)propyl methacrylate. In the first step of coating, a glass substrate was coated using a solution of metal nitrate hydrates and subsequently showed hydrophobic properties. As the second step, the spin-coated glass substrate was further coated with silica nanoparticles (SiO₂ NPs) and polycaprolactone triol (PCT) suspension, where the contents of SiO₂ NPs were fixed at 0.1 wt %, unless otherwise noted. The coated substrate exhibited hydrophilic properties. For comparison, the coating was also formulated with the SiO₂ NPs/PCT suspension without SiO₂ NPs and with 0.5 wt % SiO₂ NPs as well as by adjusting different coating layer thicknesses. The surface morphology and chemical compositions of the obtained coating materials were analyzed by field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The transparency and static contact angle of coated samples were measured by UV-visible spectrophotometry and drop shape analysis, respectively. It was concluded that our novel hybrid coating materials exhibited excellent antibacterial and antifogging properties with extremely high scratch resistance and transparency.

Heat Conduction and Antibacterial Hexagonal Boron Nitride/Polypropylene Nanocomposite Fibrous Membranes for Face Masks with Long-Time Wearing Performance

Wearing surgical masks is one of the best protective measures to protect humans from viral invasion during the 2019 coronavirus (COVID-19) outbreak. However, wearing surgical masks for extended periods will cause uncomfortable sweltering sense to users and are easy to breed bacteria. Here, we reported a novel fibrous membrane with outstanding comfortability and antibacterial activity prepared by PP ultrafine fiber nonwovens and antibacterial functionalized h-BN nanoparticles (QAC/h-BN). The thermal conductivity of commercial PP nonwovens was only 0.13 W m^-1 K^-1, but that of the QAC/h-BN/PP nanocomposite fibrous membranes can reach 0.88 W m^-1 K^-1, an enhancement of 706.5% than commercial PP nonwovens. The surface temperature of commercial PP surgical masks was 31.8 °C when the wearing time was 60 min. In contrast, QAC/h-BN/PP surgical masks can reach 33.6 °C at the same tested time, exhibiting stronger heat dissipation than commercial PP surgical masks. Besides, the antibacterial rates of QAC/h-BN/PP nanocomposite fibrous membranes were 99.3% for E. coli and 96.1% for S. aureus, and their antibacterial mechanism was based on "contact killing" without the release of unfavorable biocides. We think that the QAC/h-BN/PP nanocomposite fibrous membranes could provide better protection to people.

The Mechanisms and the Applications of Antibacterial Polymers in Surface Modification on Medical Devices

Medical device contamination caused by microbial pathogens such as bacteria and fungi has posed a severe threat to the patients' health in hospitals. Due to the increasing resistance of pathogens to antibiotics, the efficacy of traditional antibiotics treatment is gradually decreasing for the infection treatment. Therefore, it is urgent to develop new antibacterial drugs to meet clinical or civilian needs. Antibacterial polymers have attracted the interests of researchers due to their unique bactericidal mechanism and excellent antibacterial effect. This article reviews the mechanism and advantages of antimicrobial polymers and the consideration for their translation. Their applications and advances in medical device surface coating were also reviewed. The information will provide a valuable reference to design and develop antibacterial devices that are resistant to pathogenic infections.