Preparation of Antifog Hard Coatings Based on Carboxy-Functionalized Polyhedral Oligomeric Silsesquioxane Cross-Linked with Oligo(ethylene glycol)s

In this study, we prepared antifog hard coatings by heating a mixture of carboxy-functionalized polyhedral oligomeric silsesquioxane (POSS-C) and oligo(ethylene glycol)s (OEGs, HO(CH2CH2O) n H, n = 1-6) in N,N-dimethylformamide, applying the mixture onto a glass substrate, and subsequently removing the solvent via heating. In addition, we evaluated the water resistance, hardness, and antifogging performance of the coatings. In particular, the coating produced at a 2:1 functional group ratio of POSS-C to tetraethylene glycol (OEG, n = 4) coating exhibited high surface hardness (6H), as determined using pencil scratch testing. The coating remained clear after exposure to the vapor of warm water at 40 °C at a height of 2 cm for 10 s, demonstrating its antifogging property. Furthermore, no dissolution or cracking was observed when the POSS-C/OEG coating (n = 4, COOH/OH = 2:1) was immersed in water at room temperature for 1 h, confirming its water resistance. The Fourier transform infrared/attenuated total reflectance results showed the formation of ester bonds, indicating the construction of a network structure that enhanced the water resistance and hardness of the coating.

Transient Superhydrophilic Surface Modification of Polyimide by Metal Ion Beam Irradiation

Polyimide is commonly used as a substrate for flexible electronic devices because of its excellent thermal, physical, and electrical properties. To enhance the adhesion between substrates and electrodes, it is necessary to improve the hydrophilic properties of the polyimide. Various surface treatments, such as plasma treatment, laser ablation, and ultraviolet treatments, have been applied for this purpose. In this study, we demonstrated that Cu and Ti ion beam irradiation can temporarily create a superhydrophilic surface on polyimide after irradiation. When Cu or Ti ions bombarded the polyimide, the contact angle changed systematically with the beam current density and over time. We present atomic force microscopy (AFM) data for polyimide irradiated with Cu and Ti ions at different beam current densities and discuss the possible mechanisms behind the changes in the contact angle.

Design of Abrasion-Resistant, Long-Lasting Antifog Coatings

Fog formation is a common challenge for numerous applications, such as food packaging, mirrors, building windows, and freezer/refrigerator doors. Most notably, fog forms on the inner surfaces of prescription glasses and safety eyewear (particularly when used with a mask), face shields, and helmet lenses. Fogging is caused by the distortion of light from condensed water droplets present on a surface and can typically be prevented if the surface static water contact angle (θ) is less than ∼40°. Such a low contact angle can be readily achieved by either increasing the substrate surface energy or by engineering surface nanotexture. Unfortunately, such nanotexture can be readily damaged with use, while high surface energy substrates get covered with low surface energy foulants over time. Consequently, even with numerous ephemeral antifog coatings, currently there are no commercially available, durable, and permanent antifog coatings. Here we discuss the development of a new class of high-performance antifog coatings that are abrasion-resistant and long-lasting. These polyvinylpyrrolidone-based coatings, designed based on the classical Ratner-Lancaster wear model, dramatically outperform the base polymer, as well as all tested commercially available antifog coatings. Specifically, these coatings exhibit a > 400% increase in fogging time compared to base polymer, a > 50,000% increase in wear resistance, and excellent long-term antifog performance. The developed coatings also significantly outperformed all tested commercially available antifog coatings in terms of their antifog performance, wear resistance, and long-term cyclical performance. Additionally, the key design strategies employed here─incorporation of toughening agents and hydrophilic slip additives─offer a new approach to developing high-performance, durable antifog coatings based on other well-known antifog polymers.

Threshold of Surface Initiator Concentration for Polymer Brush Growth by Surface-Initiated Atom Transfer Radical Polymerization

The surface modification of various materials by grafting functional molecules has attracted much attention from fundamental research to practical applications because of its ability to impart various physical and chemical properties to the surfaces. One promising approach is the use of polymer brushes synthesized by atom transfer radical polymerization (ATRP) from surface-tethered initiators (SIs). In this study, for the purpose of controlling the grafting amounts/densities of polymer brushes, we developed a facile method to precisely regulate SI concentrations of SI layers (SILs) by serial dilution based on a sol-gel method. By simply mixing organosilanes terminated with and without an initiator group ((p-chloromethyl) phenyltrimethoxysilane (CMPTMS) and phenyltrimethoxysilane (PTMS), respectively) with tetraethoxysilane (TEOS), SI concentrations of SILs could be arbitrarily tuned precisely by varying dilution factors of (CMPTMS + PTMS)/CMPTMS (DFs, 1-107). The resulting SILs prepared at different DFs were highly smooth and transparent. X-ray photoelectron spectroscopy (XPS) also confirmed that the SIs were homogeneously distributed at the topmost surface of the SILs and their concentrations were proven to be accurately and precisely controlled from high to extremely low, comparable to theoretical values. Subsequent SI-ATRP in air ("paint-on" SI-ATRP) of two different types of monomers (hydrophobic/nonionic (2,3,4,5,6-pentafluorostyrene) and hydrophilic/ionic (sodium 4-styrenesulfonate)) demonstrated that polymer brushes with different grafting amounts/densities were successfully grafted only from SILs with DFs of 1-104 (theoretical SI concentrations: 3.9 × 10-4 ∼ 3.5 units/nm2), while at DFs of 105 and above (theoretical SI concentrations: <3.9 × 10-5 units/nm2), no sign of polymer brush growth was confirmed by thickness, XPS, and water contact angle data. Therefore, we are the first to gather evidence that the approximate threshold of SI concentration required for "paint-on" SI-ATRP might be on the order of 10-4 ∼ 10-5 units/nm2.

Transparent and Superhydrophilic Flexible Protein Films with Antifogging and Self-Cleaning Attributes

Cyanoglycoside-modified flexible protein films, exhibiting a high level of transparency of ≈46 to 83%, were successfully prepared from lysozyme and glycerol with varying amounts of amygdalin (20, 40, and 60%) using water as a solvent. The increasing percentage of amygdalin leads to a drastic improvement of the hydrophilicity of the surface with a decrease in the water contact angle to 5.6°, resulting in superhydrophilicity. The increasing percentage of amygdalin led to a significant improvement in the surface's hydrophilicity, resulting in a reduced water contact angle of 5.6° and achieving superhydrophilicity. This superhydrophilic characteristic is particularly relevant to the excellent antifogging and self-cleaning properties of the resulting protein films. In addition to enhanced flexibility, the films also exhibited considerably improved thermal stability with a 40% loading of amygdalin in the protein solution. The superior mechanical, optical, and thermal properties of amygdalin-modified films are due to the strong hydrogen bonding with the peptides of lysozyme, as evidenced by the disappearance of amide bands in the cured protein films. Therefore, these transparent protein films, with their antifogging and enhanced thermal stability properties, can be potentially used for different packaging and coating applications.

Mussel-inspired Self-assembly into Polymer Coatings of Different Molecular Weight Electrolytes for Enhanced Self-healing and Corrosion Properties

Self-healing coatings offer tremendous application prospects in the field of preventing metal corrosion because of their superior functionality. The coordination of barrier performance and self-healing ability, however, continues to be difficult. Herein, a polymer coating based on polyethyleneimine (PEI) and polyacrylic acid (PAA) with self-repairing and barrier ability was designed. Introducing the catechol group into the anti-corrosion coating increases the adhesion and self-healing efficiency of the coating, providing a guarantee for the long-term stable bonding between the anti-corrosion coating and the metal substrate. Small molecular weight PAA polymers are added to polymer coatings to increase their self-healing capabilities and corrosion resistance. Because layer-by-layer assembly creates reversible hydrogen bonds and electrostatic bonds that help the coating repair itself when it is damaged, and because the traction of small molecular weight polyacrylic acid speeds up this process. When polyacrylic acid (PAA) with a molecular weight of 2000 was present in the coating at a concentration of 1.5 mg/mL, the coating's self-healing capability and corrosion resistance were at their peak. The PEI-C/PAA45W -PAA2000 coating completed the self-healing within 10 min, and the corrosion resistance efficiency (Pe ) was as high as 90.1 %. The polarization resistance (Rp ) was maintained at 7.67×104  Ω cm2 after immersion for more than 240 h. It was better than other samples in this work. The polymer provides a new idea for the prevention of metal corrosion.

Reduced Ice Adhesion Using Amphiphilic Poly(Ionic Liquid)-Based Surfaces

Ice build-up on solid surfaces causes significant economic losses for a range of industries. One solution to this problem is the development of coatings with low ice adhesion strength. Amphiphilic poly(ionic liquid) (PIL)-based surfaces have been recently reported for antifogging/antifrosting applications. However, they have possible anti-icing properties through lowering the ice adhesion strength that have yet to be reported. Herein, we designed well-defined triblock copolymers composed of a polydimethylsiloxane component coupled with PIL segments of poly([2 (methacryloyloxy)ethyl] trimethylammonium chloride) (PMETAC), which were subsequently UV-cured with an oligo(ethylene glycol) dimethacrylate (OEGDMA) cross-linker. The structure-property relationships of the resultant semi-interpenetrating polymer networks (SIPNs) were investigated by varying the counterion (i.e., trimethylammonium bis(trifluoromethanesulfonyl)imide (TFSI^-)) and the content of the PIL segments and cross-linker. An ice adhesion strength as low as 13.3 ± 8.6 kPa was observed for the coating containing 12.5 wt % of PMETAC segment and 5 wt % of OEGDMA, which is one of the lowest values reported so far for the amphiphilic coatings. Characterization of the coatings in terms of surface features, wettability, and hydration states have enabled the elucidation of different deicing mechanisms. Self-lubrication due to the existence of nonfreezable bound water led to the obtained low ice adhesion strength. This work offers a new approach for the exploration of PIL-based icephobic coatings for practical applications.

Fundamentals and Applications of Polymer Brushes in Air

For several decades, high-density, end-tethered polymers, forming so-called polymer brushes, have inspired scientists to understand their properties and to translate them to applications. While earlier research focused on polymer brushes in liquids, it was recently recognized that these brushes can find application in air as well. In this review, we report on recent progress in unraveling fundamental concepts of brushes in air, such as their vapor-swelling and solvent partitioning. Moreover, we provide an overview of the plethora of applications in air (e.g., in sensing, separations or smart adhesives) where brushes can be key components. To conclude, we provide an outlook by identifying open questions and issues that, when solved, will pave the way for the large scale application of brushes in air.

A novel Y-shaped photoiniferter used for the construction of polydimethylsiloxane surfaces with antibacterial and antifouling properties

The simultaneous introduction of two new functionalities into the same polymeric substrate under mild reaction conditions is an interesting and important topic. Herein, dual-functional polydimethylsiloxane (PDMS) surfaces with antibacterial and antifouling properties were conveniently developed via a novel Y-shaped asymmetric dual-functional photoiniferter (Y-iniferter). The Y-iniferter was initially immobilized onto the PDMS surface by radical coupling under visible light irradiation. Afterwards, poly(2-hydroxyethyl methacrylate) (PHEMA) brushes and antibacterial ionic liquid (IL) fragments were simultaneously immobilized on the Y-iniferter-modified PDMS surfaces by combining the sulfur(VI)-fluoride exchange (SuFEx) click reaction and UV-photoinitiated polymerization. Experiments using E. coli as a model bacterium demonstrated that the modified PDMS surfaces had both the expected antibacterial properties of the IL fragments and the excellent antifouling properties of PHEMA brushes. Furthermore, the cytotoxicity of the modified PDMS surfaces to L929 cells was examined in vitro with a CCK-8 assay, which showed that the modified surfaces maintained excellent cytocompatibility. Briefly, this strategy of constructing an antibacterial and antifouling PDMS surface has the advantages of simplicity and convenience and might inspire the construction of diverse dual-functional surfaces by utilizing PDMS more effectively.

Design of Icephobic Surfaces by Lowering Ice Adhesion Strength: A Mini Review

Ice accretion can lead to severe consequences in daily life and sometimes catastrophic events. To mitigate the hazard of icing, passive icephobic surfaces have drawn widespread attentions because of their abilities in repelling incoming water droplets, suppressing ice nucleation and/or lowering ice adhesion strength. As time elapses and temperature lowers sufficiently, ice accretion becomes inevitable, and a realistic roadmap to surface icephobicity for various outdoor anti-icing applications is to live with ice but with the lowest ice adhesion strength. In this review, surfaces with icephobicity are critically categorized into smooth surfaces, textured surfaces, slippery surfaces and sub-surface textured surfaces, and discussed in terms of theoretical limit, current status and perspectives. Particular attention is paid to multiple passive anti-icing strategies combined approaches as proposed on the basis of icephobic surfaces. Correlating the current strategies with one another will promote understanding of the key parameters in lowering ice adhesion strength. Finally, we provide remarks on the rational design of state-of-the-art icephobic surfaces with low ice adhesion strength.

Large-Scale Formation of Fluorosurfactant-Doped Transparent Nanocomposite Films Showing Durable Antifogging, Oil-Repellent, and Self-healing Properties

Transparent nanocomposite films with multiple functionalities, such as durable antifogging, dynamic oleophobic, self-healing properties, were successfully prepared by a simple spin- or spray-coating method using aqueous solutions of poly(vinylpyrrolidone) (PVP) and aminopropyl-functionalized nanoclay (AMP-clay) platelets. In this study, anionic/waterborne perfluorooctanesulfonic acid potassium salt (PFOS) was premixed with the aqueous PVP solution to achieve a homogeneous dispersion of PFOS. Due to the addition of PFOS, the resulting nanocomposite film surfaces displayed statically hydrophobic (static water contact angle over 90°) and dynamically oleophobic (5 μL of oil droplets could slide off of the surface at low sliding/substrate tilt angles of less than 10°) behaviors. In spite of our nanocomposite film surface exhibiting a statically hydrophobic nature, the antifogging properties remained unchanged even after being left under high-humidity conditions (over 80% relative humidity) for 3 days. Thanks to both exceptional water-absorbing properties of PVP/AMP-clay matrices and good mobility of PFOS driven by moisture, our oil-repellent nanocomposite films could be repeatedly self-healed even after both severe physical (cutting, scratching, or falling sand abrasion) and chemical (vacuum UV oxidation) damages. Large-scale fabrication of this multifunctional nanocomposite film (30 cm × 30 cm) could also be successfully demonstrated by a spray-coating method based on in situ gel formation.

Quantitative Interpretation of Hydration Dynamics Enabled the Fabrication of a Zwitterionic Antifouling Surface

In the medical industry, zwitterionic brushes have received significant attention owing to their antifouling effect that arose from their hydration ability. However, sufficient understanding of the hydration dynamics of zwitterionic brushes is required to fabricate the precisely controlled antifouling medical devices. In this paper, we successfully show that hydration, the interaction between water molecules and zwitterionic brushes, and its dynamics can be evaluated logically and quantitatively using (i) water contact angle, (ii) molecular dynamics simulation, and (iii) Raman spectroscopy. Based on the intuitive results on hydration, we precisely optimized the antifouling property of the model medical device, a removable orthodontic retainer, with various grafting efficiencies of 2-methacryloyloxyethyl phosphate choline. As a result, the model device reduced nonspecific adsorption of proteins and bacteria, indicating an improved antifouling effect, and also inhibited the formation of a biofilm. Furthermore, the device showed excellent physical properties desirable for application in the orthodontic field, meaning the balance between the antibacterial property and mechanical strength.

The Inhibition of Icing and Frosting on Glass Surfaces by the Coating of Polyethylene Glycol and Polypeptide Mimicking Antifreeze Protein

The development of anti-icing, anti-frosting transparent plates is important for many reasons, such as poor visibility through the ice-covered windshields of vehicles. We have fabricated new glass surfaces coated with polypeptides which mimic a part of winter flounder antifreeze protein. We adopted glutaraldehyde and polyethylene glycol as linkers between these polypeptides and silane coupling agents applied to the glass surfaces. We have measured the contact angle, the temperature of water droplets on the cooling surfaces, and the frost weight. In addition, we have conducted surface roughness observation and surface elemental analysis. It was found that peaks in the height profile, obtained with the atomic force microscope for the polypeptide-coated surface with polyethylene glycol, were much higher than those for the surface without the polypeptide. This shows the adhesion of many polypeptide aggregates to the polyethylene glycol locally. The average supercooling temperature of the droplet for the polypeptide-coated surface with the polyethylene glycol was lower than for the polypeptide-coated surface with glutaraldehyde and the polyethylene-glycol-coated surface without the polypeptide. In addition, the average weight of frost cover on the specimen was lowest for the polypeptide-coated surface with the polyethylene glycol. These results argue for the effects of combined polyethylene glycol and polypeptide aggregates on the locations of ice nuclei and condensation droplets. Thus, this polypeptide-coating with the polyethylene glycol is a potential contender to improve the anti-icing and anti-frosting of glasses.

Preparation of a Ti0.7W0.3O2/TiO2 nanocomposite interfacial photocatalyst and its photocatalytic degradation of phenol pollutants in wastewater

A Ti_0.7W_0.3O₂/TiO₂ nanocomposite interfacial photocatalyst was designed and prepared for the photocatalytic degradation of phenol pollutants in wastewater. The detailed properties of the Ti_0.7W_0.3O₂/TiO₂ nanocomposite interface (NCI) were analyzed by XRD, SEM, EDX, DRS, UPS and XPS technologies, showing that anatase TiO₂ nanospheres (NSs) were uniformly dispersed on the surface of rutile Ti_0.7W_0.3O₂ nanoparticles (NPs) and formed the nanocomposite interface. The DRS and UPS results of 5 wt% Ti_0.7W_0.3O₂/TiO₂ NCI indicated a greatly broadened light response range with a wavelength shorter than 527 nm and a shorter band gap energy of 2.37 eV. The conduction band of TiO₂ NSs, Ti_0.7W_0.3O₂ NPs and 5 wt% Ti_0.7W_0.3O₂/TiO₂ NCI were measured based on the results of the valence band and band gap energy obtained via XPS and DRS, and then the energy level diagram of Ti_0.7W_0.3O₂/TiO₂ NCI was proposed. The photocatalytic degradation of phenol at Ti_0.7W_0.3O₂/TiO₂ NCI with different loading ratios of Ti_0.7W_0.3O₂ NPs was investigated under optimum conditions (i.e., pH of 4.5, catalyst dosage of 0.45 g L^-1 and phenol initial concentration of 95 ppm) under the illumination of ultraviolet visible light. Also, 5 wt% Ti_0.7W_0.3O₂/TiO₂ NCI exhibited the highest photocatalytic activity, with the initial rate constant (k) calculated as 0.09111 min^-1. After recycling six times, Ti_0.7W_0.3O₂/TiO₂ NCI showed good stability and recyclability. The involvement of superoxide radicals in the initial reaction at Ti_0.7W_0.3O₂/TiO₂ NCI was evidenced by the use of a terephthalic acid (TA) fluorescent probe. Besides, UV-Vis spectroscopy, UHPLC-MS and GC-MS technologies were used to analyze the main intermediates in the photocatalytic degradation of phenol. The probable photocatalytic degradation mechanism of phenol at Ti_0.7W_0.3O₂/TiO₂ NCI was also proposed.

Studies of polypropylene surface modified with novel beta-thiopropionate-based zwitterionic polymeric brush: synthesis, surface characterization, and significantly reduced fouling characteristics evaluation

Creating a surface with anti- or reduced fouling characteristics can lead to a reduction in nonspecific protein adsorption as well as the bacterial adhesion and platelet adhesion/activation that occur as follows. A zwitterionic polymer that consists of both cationic and anionic functionalities have been reported as an effective material to achieve these goals, likely resulted from the strongly-adsorbed hydration layer after being immersed in the physiological environment. In this investigation, a novel beta-thiopropionate-based zwitterionic monomer, 2-ammonio-3-((3-(2-hydroxy-3-(methacryloyloxy)propoxy)-3-oxopropyl)thio)-3-methylbutanoate (DPAMA), was synthesized through a facial process. And then the hydrophobic polypropylene was surface modified with this novel zwitterionic polymer through the surface-initiated atom transfer radical polymerization technique. Surface characterization analyses have been employed to investigate the modified surface properties in each reaction stage. In vitro protein adsorption, bacterial adhesion, and platelet compatibility evaluations have shown the polyDPAMA-modified polypropylene surface has significantly reduced fouling characteristics and good hemocompatibility. Henceforth, this novel zwitterionic polyDPAMA grafting PP and the associated grafting reaction scheme have great potential for future clinical applications.

Bioinspired Multifunctional Protein Coating for Antifogging, Self-Cleaning, and Antimicrobial Properties

A multifunctional coating with antifogging, self-cleaning, and antimicrobial properties has been prepared based on a mussel-inspired chimeric protein MP-KE, which is the first example that these proteins were successfully applied to fabricate antifogging surfaces. The coating exhibits super hydrophilic properties, as indicated by contact angles less than 5° and high light transmittance similar to bare glass substrates about 90%. The zwitterionic peptides of MP-KE empower water molecules to expand into thin hydrated films rapidly, providing the protein coating with diverse surface functions. Moreover, the coatings have excellent stability and a convenient preparation process because of the mussel adhesive motif of MP-KE which makes the coating anchor onto the surface strongly. As a protein material, this multifunctional coating possesses remarkable biocompatibility and has a potential application prospects in the biomedical and pharmaceutical fields.

Understanding the role of hollow sub-surface structures in reducing ice adhesion strength

The accretion of ice on exposed surfaces results in detrimental effects in many aspects of life and technology. Passive icephobic coatings, designed by strategies towards lowering ice adhesion to mitigate icing problems, have recently received great attention. In our previous studies, incorporation of hollow sub-surface structures which act as macro-scale crack initiators has been shown to drastically lower the ice adhesion on PDMS surfaces. In this study, the effects of hollow sub-surface structure geometry, such as the heights, shapes, and distributions, as well as the directions of the applied shear force, are experimentally investigated. Our results show that the number of potential macro-scale crack initiation sites dictates ice adhesion strength. The directions of the applied shear force also influence the ice adhesion strength when the potential crack length is dependent on the applied shear force direction. The inter-locking effect between ice and the coating, caused by the pre-deformation, needs to be considered if one of the dimensions of the hollow sub-surface structures approaches the millimeter scale. These results improve the understanding of the role of hollow sub-surface structures in reducing ice adhesion, providing new insights into the design principles for multi-scale crack initiator-promoted icephobic surfaces.

Metal-catechol complexes mediate ice nucleation

The capability of mediating ice nucleation is pertinent to a broad range of fields. Herein, inspired by metal-catechol coordination found in adhesive proteins in which catechol moieties can construct strong complexes with a diverse array of metal ions, we develop a platform for mediating ice nucleation based on metal-catechol complexes and demonstrate that ice nucleation can be successively mediated by varying the characteristics and valence of the metal in metal-catechol complexes.

Water drop-surface interactions as the basis for the design of anti-fogging surfaces: Theory, practice, and applications trends

Glass- and polymer-based materials have become essential in the fabrication of a multitude of elements, including eyeglasses, automobile windshields, bathroom mirrors, greenhouses, and food packages, which unfortunately mist up under typical operating conditions. Far from being an innocuous phenomenon, the formation of minute water drops on the surface is detrimental to their optical properties (e.g., light-transmitting capability) and, in many cases, results in esthetical, hygienic, and safety concerns. In this context, it is therefore not surprising that research in the field of fog-resistant surfaces is gaining in popularity, particularly in recent years, in view of the growing number of studies focusing on this topic. This review addresses the most relevant advances released thus far on anti-fogging surfaces, with a particular focus on coating deposition, surface micro/nanostructuring, and surface functionalization. A brief explanation of how surfaces fog up and the main issues of interest linked to fogging phenomenon, including common problems, anti-fogging strategies, and wetting states are first presented. Anti-fogging mechanisms are then discussed in terms of the morphology of water drops, continuing with a description of the main fabrication techniques toward anti-fogging property. This review concludes with the current and the future perspectives on the utility of anti-fogging surfaces for several applications and some remaining challenges in this field.

Zwitterionic Polymer Modified Porous Carbon for High-Performance and Antifouling Capacitive Desalination

Capacitive deionization (CDI) is an emerging technology for effective brackish water desalination to address fresh water scarcity. It is of great interest due to its high energy efficiency, environmental friendliness, and low-cost operation compared with traditional desalination technologies. However, electrode fouling, caused by dissolved organic matter and resulting in reduction of electrode electrosorption capacity and device lifespan, is an impediment to practical application of CDI. Herein, we report a novel salty water desalination electrode with excellent antifouling properties. The antifouling electrode is prepared by coating zwitterionic polymer brushes, i.e., poly(sulfobetaine methacrylate) (SBMA), on porous carbon (PC) via surface-initiated atom transfer radical polymerization. The successful coating of zwitterionic polymer on PC surface is confirmed by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and other characterizations. Coating with polySBMA did not affect the electrosorption capacity of PC electrodes and imparted antifouling properties (versus fouling by model foulant bovine serum albumin) during long-term salt removal tests (100 desalination/regeneration cycles). This is an important step toward practical application of capacitive deionization technology for brackish water desalination.

Time Evolution of Precursor Thin Film of Water on Polyelectrolyte Brush

The microscopic wetting behavior of a water film on the line-patterned surface of a polyelectrolyte brush was directly visualized using an optical microscope by dyeing procedures. Surface line patterns of 5 and 5 μm width or 10 and 5 μm width for the polyelectrolyte brush and hydrophobic monolayer, respectively, were prepared by a photolithography process, chemical vapor adsorption method, and surface-initiated polymerization. A droplet of water containing dye was placed on the line-patterned surface. In front of the contact line, a water film with a nanometer-scale thickness, referred to as a precursor film, elongated along the polymer brush line with time. The elongation velocity at the first stage increased as the brush line width increased. On the other hand, at the second stage after the macroscopic contact line stopped moving, the precursor film continued to elongate in proportion to the 0.6 power of time, independent of the brush thickness, line width, and droplet volume.

Polymer brush on surface with tunable hydrophilicity using SAM formation of zwitterionic 4-vinylpyridine-based polymer

A zwitterionic vinylpyridine-based polymeric SAM was assembled on different surfaces to obtain tunable hydrophilicity.

Recent Developments in the Preparation of Silicones with Antimicrobial Properties

This Focus Review describes state-of-the-art methods for the preparation of antimicrobial silicones. Given the diversity of antimicrobial activity and their mechanisms, the performance of these materials is highly dependent on the characteristics of the polymeric matrix. Therefore, different synthetic routes have been developed, such as 1) physical treatments, 2) chemical transformations, and 3) copolymerization. This classification is not exclusive, so some products belong to more than one class. Herein, we attempt to present a handy overview of the development of antimicrobial silicones, their most important application fields, the most relevant antimicrobial assays, and, as the title suggests, an overview of the most relevant preparation methods.

Electroassisted Functionalization of Nitinol Surface, a Powerful Strategy for Polymer Coating through Controlled Radical Surface Initiation

Coating Nitinol (NiTi) surfaces with a polymer layer has become very appealing in the past few years owing to its increased attraction in the biomedical field. Although its intrinsic properties helped ensure its popularity, its extensive implementation is still hampered by its nickel inclusion, making it sensitive to pitting corrosion and therefore leading to the release of carcinogenic Ni²⁺ ions. Among all recent ways to modify NiTi surfaces, elaboration of self-assembled monolayers is of great interest as their high order confers a reinforcement of the metal surface corrosion resistance and brings new functionalities to the metal for postmodification processes. In this work, we compare the electroassisted and thermally assisted self-assembling of 11-(2-bromoisobutyrate)-undecyl-1-phosphonic acid (BUPA) to the classical immersion process on NiTi surfaces initially submitted to a hydrothermal treatment. Among all tested conditions, the electroassisted grafting of BUPA at room temperature appears to be the most promising alternative, as it allows grafting in very short times (5-10 min), thus preventing its degradation. The thus-formed layer has been proven to be sufficient to enable the surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-(dimethylamino)ethyl methacrylate.