Rational Design of Durable Anti-fouling Coatings with High Transparency, Hardness, and Flexibility

Constructing Self-Renewing Silicone-Hydrogel Hybrid Coatings with Integrated Fouling Resistant/Release/Killing Mode toward Superior Biofouling Defense

Silicone hydrogel coatings, which integrate fouling self-release and fouling resistant properties, represent a groundbreaking advancement in environmentally friendly biofouling mitigation, but are still plagued by static fouling conditions and longevity concerns. In this work, Schiff base chemistry and a sol-gel technique is leverage to develop degradable silicone-hydrogel hybrid antifouling coatings by incorporating amphiphilic silicone-based polymers with terephthalaldehyde (TPE) and cinnamaldehyde (CAL). The synergistic combination of flexible Si─O bonds in the polymer backbone and reversible covalent crosslinking imparts exceptional flexibility (hardness of 0.135), controlled degradability, and dynamic surface self-renewal capabilities, ensuring sustained antifouling performance through surface dynamic stability. During degradation, the amphiphilic polymers will self-enrich at the interface, forming a dual-functional surface that combines fouling release and fouling resists properties. The antibacterial TPE and natural CAL, anchored within the polymer network, exhibit environment-responsive release behavior, effectively suppressing bacterial proliferation and biofilm adhesion. The optimized coating achieves a bactericidal rate of 98.8%, an anti-bacterial adhesion rate of 99.8%, and a predicted anti-fouling longevity of 5.5 years with a thickness of 200 µm. This innovative approach enables a new anti-biofouling coating that involves unique fouling control mode, thereby meeting the diverse application.

Electron-Withdrawing Effects for Tailoring Oxidative-Stress-Mediated Coating in Marine Antifouling

Oxidative stress derived from excess reactive oxygen radicals (ROS) induces cellular damage, apoptosis, and necrosis, thus effective biofouling control by directly inhibiting primary membrane formation. However, the oxidative stress produced that does not rely on additional energy still is a challenge. Herein, an oxidative-stress-mediated marine antifouling polyurea coating is prepared leveraging the strong electron absorption effect of C═N. Given the structure of the urethane bond, the reversible reaction energy barrier of the dynamic urethane bond can be reduced, thereby enabling the urethane bond to be broken without the need for additional energy. The alkyl radical (R·) originating from the oxime-urethane bond can mediate the induction of oxidative stress in cells and microbial death, thus preserving exceptional antifouling properties and resisting most of the organism to adhere on the substrates. Notably, the coating indicates satisfactory antibacterial and antialgae performance and exhibits 8 months of marine field antifouling performance. In addition, the electron structure is investigated by theoretical calculation, and the interface behavior is investigated by molecular dynamics simulation. This work presents a pioneering example of the construction of oxidative-stress-mediated coating, which might be a judicious design strategy for an environmentally friendly marine antifouling coating.

Flexible Waterborne Silicone-Based Coating with High Mechanical, Stretchable, and Durable Antismudge Properties

Eco-friendly, flexible, and fluorine-free antismudge coatings have broad applications in soft substrates such as fabrics, premium leather, synthetic leather, and flexible electronic devices. However, developing antismudge coatings possessing both excellent durability and desirable softness and stretchability remains a formidable challenge. Herein, two waterborne silicone-based emulsions were prepared via emulsion inversion point method, using high-molecular-weight divinyl-terminated poly(dimethylsiloxane) (ViPDMSVi) and methyl vinyl MQ resin as raw materials, respectively, with polyether-modified silicone (D(PDMS)PE) compounding with sodium dodecyl sulfate (SDS) as emulsifiers. Subsequently, poly(methylhydrosiloxane) emulsion (PHSE) was utilized as a cross-linking agent, and a highly comprehensive waterborne silicone-based coating was successfully fabricated through hydrosilylation among the three types of emulsions. Owing to rational structural design and aqueous-based strategy, the coating achieves the integration of high mechanical properties (≥3.5 MPa tensile strength and 214% elongation) and stretchability, outstanding flexibility (the glass transition temperature below -105 °C), high transparency, excellent self-cleaning, and antismudge performance. Moreover, the exceptional durability of the coating is evidenced by maintaining antismudge properties after rigorous treatments, such as 24 h of UV irradiation, immersion in acid, alkali, and salt solutions for 24 h, 500 cycles of mechanical abrasion under a load of 1000 g, etc. This work provides a feasible pathway for manufacturing high-performance antismudge coatings suitable for soft substrates in a green and sustainable manner.

Anti-smudge superhard transparent coatings via ultra-small nanoparticle pattern surfaces

Anti-smudge coating materials have a broad prospect, but they are susceptible to wear from nails and sand. Therefore, the potential application of such coatings on glass substrates needs coating features such as superhardness and high transparency. However, realizing these key properties combined with anti-smudge function is significantly challenging. In this work, we show a conceptional nanoparticle pattern designing strategy of materials, inspired by stepping on cobblestone roads with the foot feeling of only the hardness of stones. Realize the nanoparticle pattern surface of "cobblestone roads" via facile and scalable interfacial reactions within a molecular compatible system, to successfully achieve the desired coating material properties including anti-smudge, superhardness, and high transparency. The coating was composed of tensely crosslinked sub-10 nm building blocks that bear an anti-smudge molecular layer, exhibiting undistinguished inorganic phase behavior when it was subjected to external forces within the contact point of micro- or above 10 nm nanoscale.

Waterborne Liquid-like Coatings with High Transparency, Superior Scratch Resistance, and Antismudge Properties

The aqueous formulation of antismudge coatings is a crucial step for environmental protection and pollution reduction. However, the inferior mechanical durability of waterborne antismudge coatings poses challenges for their practical application. Herein, we developed a fully waterborne antismudge coating with excellent scratch resistance by preparing hyperbranched amine-rich polysiloxane (HySPx) for antismudge ability and epoxy-rich zirconium-based aqueous solution (ZAS) for mechanical performance. The former is obtained by combining SPx, polydimethylsiloxane modified by 3-isocyanatopropyltriethoxysilane (IPTS), with 3-aminopropyltriethoxysilane (KH550), and the latter is synthesized using zirconium propoxide solution (TPOZ) with 3-glycidyloxypropyltrimethoxysilane (KH560). This report investigates the effects of the chain length and content of SPx on the performance of the coating. The results indicate that the coating exhibits optimal comprehensive performance when the molecular weight of polydimethylsiloxane is 4.5 kDa, and the mass fraction of SPx in HySPx is 1.5%. The coating possesses high transparency similar to glass, good adhesion (≈3 MPa) to various substrates, high hardness (8H), flexibility (2.5 mm bending radius), and exceptional antismudge property. More importantly, the coating can still maintain excellent antismudge property even after enduring 400 cycles of abrasion with steel wool. Furthermore, the rapid enrichment of polydimethylsiloxane on the coating surface endows the coating with excellent lubrication ability, allowing most common liquid stains to slide off the coating surface. Moreover, the rewritability of the coating remains stable even after writing traces that have persisted on its surface for several weeks. This coating is anticipated to be utilized for protecting foldable electronic screens, vehicles, and other fields.

An investigation of a strengthening polysaccharide interfacial membrane strategy utilizing an anionic polysaccharide-alkaline ligand interfacial assembly for all-liquid printing

The applications of polysaccharides as emulsifiers are limited due to the lack of hydrophobicity. However, traditional hydrophobic modification methods used for polysaccharides are complicated and involve significant mechanical and thermal losses. In this study, soy hull polysaccharide (SHP) and terminally aminopropylated polydimethylsiloxane (NPN) were selected to investigate the feasibility of a simple and green interfacial membrane strengthening strategy based on the interfacial polymerization of anionic polysaccharides and fat-soluble alkaline ligands. Our results show that deprotonated SHP and protonated NPN can be complexed at the water/oil (W/O) interface, reduce interfacial tension, and form a strong membrane structure. Moreover, they can quickly form a membrane at the W/O interface upon the moment of contact to produce stable all-liquid printing products with complex patterns. However, the molecular weight of NPN affects the complexation reaction. Consequently, this study has long-term implications to expanding the areas of application for anionic polysaccharides.

Robust Superhydrophobic Composite Fabric with Self-Healing and Chemical Durability

Superhydrophobic fabrics with multiple functions have become a research hotspot. However, it is challenging to make self-healing mechanically robust and eco-friendly superhydrophobic fabrics, which are limited by complex fabrication processes and excessive use of environmentally unfriendly solvents during fabrication. Herein, inspired by the secretion of a waxy substance from the surface of lotus leaves to restore water repellency, self-healing superhydrophobic composite fabrics (as-synthesized PA66/6-PET@Tico) are obtained by constructing a papillary TiO2 and tentacle-like fluorinated acrylate polymer (FCB015) coating on polyester-nylon composite fabrics using two-step hydrothermal method. The result indicates that PA66/6-PET@Tico with hierarchical micro/nanostructure exhibits excellent superhydrophobic and self-healing properties. Compared with FCB015 coated fabric, the contact angles (CA) of water and soybean oil rise to 172.2° and 166.8° from 137.4° and 98.8°, respectively. After mechanical abrasion, PA66/6-PET@Tico recovers a water contact angle (WCA) of 165.6° at room temperature. The WCA remains higher than 155° after 18 h of chemical corrosion. Furthermore, the bacterial inhibition rates of PA66/6-PET@Tico for Staphylococcus Aureus and Escherichia Coli are 99.90 and 98.38%, respectively. In this work, a new idea is proposed for designing a simple and effective self-healing superhydrophobic coating, expecting to promote the large-scale industrial production and application of functional surfaces.

One-step synthesis of functional slippery lubricated coating with substrate independence, anti-fouling property, fog collection, corrosion resistance, and icephobicity

Ranging from industrial facilities to residential infrastructure, functional surfaces encompassing functionalities such as anti-fouling, fog collection, anti-corrosion, and anti-icing play a critical role in the daily lives of humans, but creating these surfaces is elusive. Bionic dewetting and liquid-infused surfaces have inspired the exploitation of functional surfaces. However, practical applications of these existing surfaces remain challenging because of their inherent shortcomings. In this study, we propose a novel functional slippery lubricated coating (FSLC) based on a simple blend of polysilazane (PSZ), silicone oil, and nano silica. This simple, nonfluorine based, and low-cost protocol promotes not only hierarchical micro-nano structure but also favorable surface chemistry, which facilitates robust silicone oil adhesion and excellent slippery properties (sliding angle: ∼1.6°) on various solid materials without extra processing or redundant treatments. The highly integrated competence of FSLC, characterized by robustness, durability, strong adhesion to substrates, and the ability for large-area preparation, render them ideal for practical production and application. The proposed FSLC holds outstanding application potentials for anti-fouling, self-cleaning, fog collection, anti-corrosion, and anti-icing functionalities.

Transparent anti-fingerprint glass surfaces: comprehensive insights into theory, design, and prospects

With the advancement of information technology, touch-operated devices such as smartphones, tablets, and computers have become ubiquitous, reshaping our interaction with technology. Transparent surfaces, pivotal in the display industry, architecture, and household appliances, are prone to contamination from fingerprints, grease, and dust. Such contaminants compromise the cleanliness, aesthetic appeal, hygiene of the glass, and the overall user visual experience. As a result, fingerprint prevention has gained prominence in related research domains. This article delves into the primary characteristics of fingerprints and elucidates the fundamental mechanisms and components behind their formation. We then explore the essential properties, classifications, and theoretical foundations of anti-fingerprint surfaces. The paper concludes with a comprehensive review of recent advancements and challenges in transparent superlyophobic fingerprint-resistant surfaces, projecting future trajectories for transparent fingerprint-resistant glass surfaces.

Bio-Based Waterborne Polyurethane Coatings with High Transparency, Antismudge and Anticorrosive Properties

Green and environment-friendly preparation are of the utmost relevance to the development of transparent antismudge coatings. To prepare a waterborne polyurethane (WPU) coating with antismudge property, it is challenging to balance the stability of dispersion and the antismudge property of coating. Herein, we prepare a transparent bio-based WPU coating grafted with a minor proportion of poly(dimethylsiloxane) (WPU-g-PDMS) using renewable castor oil, monocarbinol-terminated PDMS, hexamethylene diisocyanate trimer, and 2,2-bis(hydroxymethyl)propionic acid as raw materials. Effects of the dosage of monocarbinol-terminated PDMS, the curing temperature, and the curing time on the antismudge performance were studied. Results showed that rigorous stirring (3000 rpm) is necessary to obtain a stable WPU-g-PDMS dispersion with a storage time longer than 6 months. A high curing temperature (>160 °C) and a period of curing time (>1 h) are indispensable to obtain the excellent antismudge property because they would facilitate the grafted low-surface-tension PDMS chains to migrate from the interior to the coating surface. The facts that simulated contaminated liquids such as water, HCl solution, NaOH solution, artificial blood, and tissue fluid could slide off easily and cleanly, and marker ink lined on the coating surface could shrink, indicated that the WPU-g-PDMS coating has good antismudge properties, which could be self-compensated shortly after deterioration. Due to the high cross-linking degree caused by multifunctional polyol and isocyanate, the WPU-g-PDMS coating has high hardness and good anticorrosive performance. The antismudge functionalization and waterborne technology of bio-based polyurethane coatings proposed in this work could be a promising contribution to the green and sustainable development of functional coatings. This kind of WPU-g-PDMS coating is expected to protect and decorate electronic screens, vehicles, and buildings, especially endoscopes.

Omniphobic liquid-like surfaces

Liquid-repellent surfaces, especially smooth solid surfaces with covalently grafted flexible polymer brushes or alkyl monolayers, are the focus of an expanding research area. Surface-tethered flexible species are highly mobile at room temperature, giving solid surfaces a unique liquid-like quality and unprecedented dynamical repellency towards various liquids regardless of their surface tension. Omniphobic liquid-like surfaces (LLSs) are a promising alternative to air-mediated superhydrophobic or superoleophobic surfaces and lubricant-mediated slippery surfaces, avoiding fabrication complexity and air/lubricant loss issues. More importantly, the liquid-like molecular layer controls many important interface properties, such as slip, friction and adhesion, which may enable novel functions and applications that are inaccessible with conventional solid coatings. In this Review, we introduce LLSs and their inherent dynamic omniphobic mechanisms. Particular emphasis is given to the fundamental principles of surface design and the consequences of the liquid-like nature for task-specific applications. We also provide an overview of the key challenges and opportunities for omniphobic LLSs.

Super-Slippery Poly(Dimethylsiloxane) Brush Surfaces: From Fabrication to Practical Application

Superwetting surfaces with special slippery performances have been the focus of practical applications and basic research for decades. Compared to superhydrophobic/superoleophobic and slippery liquid-infused porous surfaces (SLIPS), liquid-like covalently attached poly(dimethylsiloxane) (PDMS) brush surfaces have no trouble in constructing the micro/nanostructure and the loss of infused lubricant, meanwhile, it can also provide lots of new advantages, such as smooth, transparent, pressure- and temperature-resistant, and low contact angle hysteresis (CAH) to diverse liquids. This paper focuses on the relationship between the wetting performance and practical functional application of PDMS brush surfaces. Recent progress of the preparation of PDMS brush surfaces and their super-slippery performances, with a special focus on diverse functional applications were summarized. Finally, perspectives on future research directions are also discussed.

Organoids and microphysiological systems: Promising models for accelerating AAV gene therapy studies

The FDA has predicted that at least 10-20 gene therapy products will be approved by 2025. The surge in the development of such therapies can be attributed to the advent of safe and effective gene delivery vectors such as adeno-associated virus (AAV). The enormous potential of AAV has been demonstrated by its use in over 100 clinical trials and the FDA’s approval of two AAV-based gene therapy products. Despite its demonstrated success in some clinical settings, AAV-based gene therapy is still plagued by issues related to host immunity, and recent studies have suggested that AAV vectors may actually integrate into the host cell genome, raising concerns over the potential for genotoxicity. To better understand these issues and develop means to overcome them, preclinical model systems that accurately recapitulate human physiology are needed. The objective of this review is to provide a brief overview of AAV gene therapy and its current hurdles, to discuss how 3D organoids, microphysiological systems, and body-on-a-chip platforms could serve as powerful models that could be adopted in the preclinical stage, and to provide some examples of the successful application of these models to answer critical questions regarding AAV biology and toxicity that could not have been answered using current animal models. Finally, technical considerations while adopting these models to study AAV gene therapy are also discussed.