Transparent Omniphobic Coating with Glass‐Like Wear Resistance and Polymer‐Like Bendability

Liquid-Like Surfaces with Enhanced De-Wettability and Durability: From Structural Designs to Potential Applications

Liquid-like surfaces (LLSs) with dynamic repellency toward various pollutants (e.g., bacteria, oil, and ice), have shown enormous potential in the fields of biology, environment, and energy. However, most of the reported LLSs cannot meet the demands for practical applications, particularly in terms of de-wettability and durability. To solve these problems, considerable progress has been made in enhancing the de-wettability and durability of LLSs in complex environments. Therefore, this review mainly focuses on the recent progress in LLSs, encompassing designed structures and repellent capabilities, as well as their diverse applications, offering greater insights for the targeted design of desired LLSs. First, a detailed overview of the development of LLSs from the perspective of their molecular structural evolution is provided. Then highlight recent approaches for enhancing the dynamic de-wettability and durability of LLSs by optimizing their structural designs, including linear, looped, crosslinked, and hybrid structures. Later, the diverse applications and unique advantages of recently developed LLSs, including repellency (e.g., liquid anti-adhesion/transportation/condensation, anti-icing/scaling/waxing, and biofouling repellency) are summarized. Finally, Perspectives on potential innovative advancements and the promotion of technology selection to advance this exciting field are offered.

Rational Design of Highly Comprehensive Liquid-Like Coatings with Enhanced Transparency, Concerted Multi-Function, and Excellent Durability: A Ternary Cooperative Strategy

Durable repellent surfaces of high transparency find key applications in daily life and industry. Nevertheless, developing anti-reflective coatings with omni-repellency, concerted multi-function, and desirable durability remains a daunting challenge. Here, a highly comprehensive coating is designed based on the combination of structural design and molecular design. The resulting silica hybrid coating not only manifests enhanced transparency and exceptional omniphobicity, but also achieves integration of multi-function (e.g., anti-smudge, anti-icing, and anti-corrosion). The unprecedented durability of the coating is evidenced by maintaining slipperiness after rigorous treatments, such as 2.5 × 105-cycle mechanical abrasion with a high loading pressure of 100 kPa, 1000-cycle adhesion/peeling and soaking in extreme pH solutions, etc. This work provides a design blueprint for manufacturing versatile and durable coatings for wide-ranging applications.

Solvent-Free and UV-Cured Epoxy Silicone Coating with Excellent Wear Resistance and Antismudge Properties

Transparent, hard, and flexible multifunctional coatings have a wide range of applications; however, most of them need organic solvents. Here, we present a solvent-free and UV-cured coating made from fluorinated epoxy MTQ silicone resin combined with branched triepoxy siloxane as the reactive diluent. After UV-initiated ring-opening polymerization in the presence of a triarylsulfonium hexafluoroantimonate catalyst, the resultant cured coating exhibits high transparency (∼92%, 550 nm), pencil hardness (7H), and flexibility (1 mm bending diameter) due to the formed organic-inorganic nanostructures in a highly cross-linked network. The triepoxy siloxane significantly reduces the viscosity before curing and increases cross-link density of the coating. The coating without any volatile content shows a smooth surface with low roughness (Rq = 0.46 nm) and delivers an anti-smudge ability owing to perfluorinated chains inherited from the MTQ resin. Furthermore, even after 3000 abrasion cycles, the coating still has a water contact angle greater than 90°, displaying excellent wear resistance. Our work provides a promising way to access high-performance multifunctional coatings in a more sustainable manner.

Design of PDMS/PAN composite membranes with ultra-interfacial stability via layer integration

The interfacial interaction between the selective layer and porous substrate directly determines the separation performance and service lifetime of functional composite membranes. Till now, almost all reported polymeric selective layers are physically in contact with the substrate, which is unsatisfactory for long-term operation. Herein, we introduced a functional composite membrane with ultra-interfacial stability via layer integration between the polydimethylsiloxane selective layer and polyacrylonitrile substrate, where a facile light-triggered copolymerization achieved their covalent bonding. The critical load for the failure of the selective layer is 45.73 mN when testing the interfacial adhesion, i.e., 5.8 times higher than that before modification and significantly higher than previous reports. It also achieves superior pervaporation performance with a separation factor of 9.54 and membrane flux of 1245.6 g m-2 h-1 feeding a 1000 ppm phenol/water solution at 60 °C that is significantly higher than the same type of polymeric ones. Not limited to pervaporation, such a strategy sheds light on the design of highly stable composite membranes with different purposes, while the facile photo-trigged technique shows enormous scalability.

Long-Term Stable Superlubricity Coatings Enabled by the Interaction between the Polydimethylsiloxane Brush and Silicone Oil

Recently, materials with superlubricity captured widespread attention on account of their great potential in energy savings and environmental protection. However, certain issues still remain to be solved for the traditional materials, such as the dependence on strict conditions and an unstable superlubricity state. Herein, a long-term stable superlubricity coating was prepared using a low-cost and simple method via an epoxy-based coating with polydimethylsiloxane (PDMS) brushes under silicone oil (SO) lubrication conditions. Compared with the pure epoxy resin matrix, the friction coefficient and wear track width of the superlubricity coating with the optimal amount of 6 wt % PDMS are reduced to 0.006 and 50.9 μm (reduced by 10-fold and 5.6-fold decrease, respectively). In addition, the coating can maintain a stable superlubricity state during a 5 h tribological test. The superlubricity of the coating results from the synergistic lubrication effect of the PDMS brush and SO. First, PDMS brushes with high-stretched conformation due to the swelling effect of the SO can significantly reduce friction. Second, a stable oil film is generated between the contact surfaces, which significantly improves the frictional performance. Moreover, the PDMS incorporated into the coating matrix, along with oil-swelling PDMS brushes on the surface, is highly beneficial for enhancing corrosion resistance of the epoxy resin matrix. Such an epoxy-based coating with long-term stable superlubricity is considered as a potential lubricating and protective surface for tribological components for long-term service.

Preparation and characterization of hemicellulose films reinforced with amino polyhedral oligomeric silsesquioxane for biodegradable packaging

Biomass is one of the powerful alternatives to petroleum-based packaging materials. Herein, carboxymethyl hemicellulose (CMH) based films (CPF) were prepared using a convenient strategy. The chains of CMH provided the necessary supporting matrix, and the aminopropyl polyhedral oligomeric silsesquioxane (POSS-NH2) regulated the thermal and barrier properties of the CPF. The secondary amide groups and hydrogen bond were appeared in chemical structure, and SEM-EDS results indicated the preferable dispersion and compatibility of POSS-NH2 in CPFs. The thermal degradation temperature (Tonset > 260 °C), the coefficient of linear thermal expansion and glass transition temperature (Tg > 130 °C) have been improved by introduction of POSS-NH2. The tensile strength of CPF showed a higher level of 39.43 MPa with the POSS-NH2 loading of 20 wt%, which was 18.8 % higher than that of CMH film. More importantly, water vapor barrier property of films almost improved by two times, and its value is reduced to 18.82 g m-2 h-1. The shelf life of blueberry was effectively extended by the CPF coating for one week compared with commercial PE film. Therefore, CPF films displayed effective thermal performances, water vapor barrier characteristic and biodegradability, which might be exploited in packaging material for food application.

Flexible Transparent Hydrophobic Coating Films with Excellent Scratch Resistance Using Si-Doped Carbonized Polymer Dots as Building Blocks

Flexible transparent hydrophobic coating films with excellent scratch resistance have important applications in many fields, especially for optical materials. Herein, a hydrophobic composite coating film was prepared and used as a polymer film protective material by combining 3-glycidyloxypropyltrimethoxysilane (GPTMS)-modified Si-doped carbonized polymer dots (Si-CPDs) with mono-trimethoxysilyl-terminated poly(dimethyl siloxane) (PDMS). The Si-CPDs derived from tetramethyl disiloxane propylamine tetraacetic acid and multi-amino oligosiloxanes were successfully prepared via one-step hydrothermal method and then grafted by GPTMS to obtain modified Si-CPDs (mSi-CPDs). Among them, mSi-CPDs act as a matrix layer, and PDMS acts as a low-surface energy layer. Cross-linking the Si-O-Si network of the coating film was formed through sol-gel chemistry. Driven by the hydrophilic-hydrophobic effect, PDMS trends to aggregate at the film surface, thus avoiding the phase separation which can affect transparency. The highly cross-linked network and the presence of hard silica core provide a high hardness to stand the steel-wool scratch. Flexible polymer chains impart the coating film an outstanding bendability. Introduction of PDMS makes the coating film possess hydrophobicity and anti-graffiti function.

Inorganic-Organic Silica/PDMS Nanocomposite Antiadhesive Coating with Ultrahigh Hardness and Thermal Stability

Antiadhesive surfaces have been gaining continuous attention, because of the scientific and industrial significance. Slippery surfaces and antismudge coatings with antiadhesive behavior have been readily designed and prepared. However, improving robustness of the surfaces, especially the simultaneous demonstration of features of high hardness, excellent adhesion to different substrates, and high thermal stability, is constantly challenging. Herein, we present a silica/polydimethylsiloxane (PDMS) nanocomposite coating (SPNC), wherein silica acts as a consecutive phase and nanophased PDMS is covalently embedded. The nanoconfined PDMS phase exhibits enhanced thermal stability and endows SPNC with slippery behavior; meanwhile, enrichment of PDMS on the surface renders a gradient composition of the coating. Accordingly, the inorganic-organic SPNC simultaneously displays a high nanoindentation hardness of 3.07 GPa and a pencil hardness over 9H, outstanding thermal stability of the slippery performance up to 400 °C, and excellent adhesion strength to different substrates. Additionally, SPNC exhibits high optical transparency, flexibility, resistance to bacterial clone, and chemical corrosion. With the scalable fabrication process, it can be envisioned that the antiadhesive coating with unprecedented comprehensive merits in this work has significant potentials for large-area applications, especially under severe service environments.

Progress in Polymer-Ceramic Hybrid Antifouling Coatings

Simultaneous realization of superior mechanical and antifouling properties is critical for a coating. The use of stereoscopic polysiloxanes in place of linear polysiloxanes to fabricate antifouling coatings can combine properties of organic and inorganic materials, i.e., they can exhibit both high hardness and wear resistance from inorganic components as well as the flexibility and tunability from organic components. This strategy is used to prepare hard yet flexible antifouling coatings or polymer-ceramic hybrid antifouling coatings. In this mini-review, we report the recent advances in this field. Particularly, the effects of stereoscopic polysiloxane structures on their mechanical and antifouling properties are discussed in detail.

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.

Non-isocyanate Polyurethane Coating with High Hardness, Superior Flexibility, and Strong Substrate Adhesion

Flexible hard coatings with strong adhesion are critical requirements for several foldable devices and marine applications; however, only a few such coatings have been reported. Herein, we report a non-isocyanate polyurethane (NIPU) coating prepared by the epoxy-oligosiloxane nanocluster-amine curing reaction and cyclic carbonate-amine polyaddition, where the former provides the coating with ceramic-like hardness and polymer-like flexibility while the latter polymerization results in NIPU with strong substrate adhesion. The coating is transparent (>92% transmittance), hard (5-7 H), and flexible (2 mm bending diameter). It has strong adhesion to various substrates including aluminum alloy, titanium, steel, glass, ceramic, epoxy, and polyethylene terephthalate (2-8 MPa), which can be attributed to the high density of polar groups in NIPU. Moreover, we can facilely endow the coating with anti-icing, self-cleaning, and anti-smudge capabilities by incorporating amine-terminated low-surface-tension polydimethylsiloxane (PDMS) to replace a part of the amine curing agent. Particularly, the mechanical properties of NIPU coatings are only slightly affected by the introduction of low-content PDMS since it intends to enrich on the surface. The novel coating has promising future for use in fields of foldable devices and marine applications.

Shear-Stable Polymer Brush Surfaces

Research on polymer brushes (PBs) has aroused great interest due to their wide range of applications in lubrication, antifogging, antifouling, self-cleaning, antiadhesion, antibacterial effects, and so forth. However, the weak mechanical strength, especially the low bond strength between the PBs and the substrate surface, is a long-standing challenge for its practical applications, which is directly related to the service life of the PB surface. Fortunately, the imperfection of the PB surface was gradually solved by researchers by combining the action of the chemical and physical anchoring strength, and many shear-stable PB surfaces were developed. In this Perspective, we present recent developments in the studies of shear-stable PBs. Conventional strategies that altered the structure of PB chain methods, including increasing grafted density, cross-linking of PBs, cyclic PBs, and so forth, are introduced briefly. The systematic subsurface grafting of the polymer brush (SSPB) strategy was introduced emphatically. The SSPB method grafted PB into the subsurface with considerable depth and gave a robust and reusable PB layer, which provided an approach for tackling the shear-resistance issue. Besides, the robust hydrophobic poly(dimethylsiloxane) (PDMS) brush surface that lubricated itself in air was also introduced. Finally, we provide a synopsis and discuss the outlook of the shear-stable PB surface.

Judicious Design and Rapid Manufacturing of a Flexible, Mechanically Resistant Liquid-Like Coating with Strong Bonding and Antifouling Abilities

Fluorine-free liquid-repellent coatings have been highly demanded for a variety of applications. However, rapid formation of coatings possessing outstanding oil repellency and strong bonding ability as well as good mechanical strength (e.g., bendability, impact resistance, and scratch resistance) remains a grand challenge. Herein, a robust strategy to rapidly create fluorine-free oil-repellent coatings in only 30 s via rational design of a semi-interpenetrating polymer network structure is reported. The resulting coating manifests strong bonding capability both in air and underwater. More importantly, it not only provides unprecedented oil repellency, even to high-viscosity crude oil, but also achieves both excellent bendability and hardness. This simple yet effective design strategy opens up a new avenue to manufacture multifunctional materials and devices with desirable features and structural complexities for applications in sustainable antifouling, drag reduction, nondestructive transportation, liquid collection, and biomedicine, among other areas.

Facile Preparation of a Transparent and Rollable Omniphobic Coating with Exceptional Hardness and Wear Resistance

The encapsulating film for the touchscreen of a foldable smartphone consists of a flexible polymer layer covered by a hard coating and an antismudge coating, and the two coating layers are currently deposited via separate steps. This paper reports the preparation of a bilayer bifunctional coating via the deposition of a single polymer mixture. The base material for the coating is a ladder-like polysilsesquioxane (LASQ) that is derived from the sol-gel chemistry of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Reacting a limiting amount of the liquid antismudge agent FP-COOH, which is a perfluorinated poly(propylene oxide) bearing a terminal carboxyl group, with LASQ yields m-LASQ-FP, a mixture of unreacted LASQ, and a graft copolymer LASQ-FP. m-LASQ-FP at a fluorine mass fraction of 6.0% is photocured to yield a coating with a surface energy of 12.3 ± 1.5 mJ/m². At a thickness of 40 μm, the coating has at 500 nm a transmittance of >99% measured against its glass substrate, a remarkable nanoindentation hardness H value of 1.4 GPa, and a pencil hardness of > 9H. After being abraded for 300 strokes under a pressure of 26 kPa with steel wool, the coating exhibits no noticeable degradation in its ink contraction properties. At a thickness of 10 μm on a poly(ethylene terephthalate) film, the coating can undergo inward (on the inner surface of the bend) and outward bending to radii <1 and <2 mm, respectively, without cracking. Aside from being a superb candidate as a protective antismudge coating for foldable smartphones, this marvelous material should also have many other applications.

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

Highly transparent, durable, flexible and smooth coatings with excellent anti-fouling properties have broad applications on cars, windows, and touch screens. However, the coexistence of these multi-functions is difficult to achieve in a single coating material. Here, a coating is developed with excellent performance of high transparency (98.8%), anti-fouling, high hardness (8H), and flexibility simultaneously (TAHF coating). In the material design, methyl etherified melamine formaldehyde resin, hexamethylene diisocyanate trimer, and mono-aminopropyl terminated polydimethylsiloxane (NH₂-PDMS) were used as a polymer matrix to provide surface hardness, a cross-linker was used to provide toughness, and omniphobic groups from NH₂-PDMS were used to provide anti-fouling performance. The TAHF coating has excellent liquid repellence even after six months of outdoor exposure, 260 h of UV light exposure, and 1500 wear and 2000 bending cycles, and its chemical shielding performance is superior to that of a commercial anti-corrosive coating. This strategy would provide a new route for the design of multifunctional anti-fouling coatings for practical applications.

Multifunctional Hard Yet Flexible Coatings Fabricated Using a Universal Step-by-Step Strategy

Hard yet flexible coatings with multi-functionalities are useful for foldable displays and marine industries but rare. In this study, a highly cross-linked multifunctional hybrid coating with ceramic-like hardness and polymer-like flexibility is reported. The coating is prepared via a step-by-step strategy, where two types of epoxy-oligosiloxane nanoclusters are first synthesized by sol-gel chemistry, and amine-terminated curing agents are used to cross-link them at room temperature. The coating is highly transparent (>92% transmittance), hard (6-7H), and flexible (10 mm bending diameter) because of the unique combination of siloxane nanoclusters and polymer networks. Meanwhile, since the coating contains fouling-resistant telomer and low-surface-tension liquid lubricant polydimethylsiloxane (PDMS), it exhibits excellent anti-biofouling and self-cleaning properties. The results indicate that the mechanical and antifouling properties of the coating can be easily tuned and prove that the step-by-step strategy is a promising and universal method. The novel coatings can meet the needs of applications in foldable displays, marine industries, and other fields.

Ice-Shedding Polymer Coatings with High Hardness but Low Ice Adhesion

Ice readily sheds from weak oil-swollen polymer gels but tends to adhere to mechanically robust coatings. This paper reports bilayer coatings that simultaneously possess high bulk hardness but low ice adhesion. These coatings are prepared by cocuring a triisocyanate, P#'-g-PDMS [a methacrylate polyol bearing poly(dimethylsiloxane) (PDMS) side chains with # being 1, 2, or 3 and g denoting graft], and optionally a methacrylate polyol P#. The self-assembly of the system during coating formation yields a PDMS brush layer on the surface of the cross-linked polyurethane matrix. After the surface PDMS layer is lubricated with a silicone oil, this coating exhibits an ice adhesion τ that is 10 000-fold lower than that of a triisocyanate/P# coating. Ice slides under its own weight on such a coating at a tilt angle of 3°. Yet, the coating matrix is harder than poly(ethylene terephthalate), a widely used plastic. Additionally, such a coating maintains its low τ values for more than 10 consecutive icing/deicing cycles. Subsequent increases in τ are reversed by allowing time for the replenishment of the depleted surface lubricant with that released from the coating matrix. This design opens the door for effective yet hard ice-shedding polymer coatings.

Superior Hard but Quickly Reversible Si-O-Si Network Enables Scalable Fabrication of Transparent, Self-Healing, Robust, and Programmable Multifunctional Nanocomposite Coatings

A coating with programmable multifunctionality based on application requirements is desirable. However, it is still a challenge to prepare a hard and flexible coating with a quick self-healing ability. Here, a hard but reversible Si-O-Si network enabled by aminopropyl-functionalized poly(silsesquioxane) and triethylamine (TEA) was developed. On the basis of this Si-O-Si network, basic coatings with excellent transparency, hardness, flexibility, and quick self-healing properties can be prepared by filling soft polymeric micelles into hard poly(silsesquioxane) networks. The highly cross-linked continuous network endows the coating with a hardness (H = 0.83 GPa) higher than those of most polymers (H < 0.3 GPa), while the uniformly dispersed micelles decrease the Young's modulus (E = 5.89 GPa) to a value as low as that of common plastics, resulting in excellent hardness and flexibility, with an H/E of 14.1% and an elastic recovery rate (W_e) of 86.3%. Scratches (∼50 μm) on the coating can be healed within 4 min. The hybrid composition of poly(silsesquioxane) networks also shows great advantages in integration with other functional components to realize programmable multifunctionality without diminishing the basic properties. This nanocomposite design provides a route toward the preparation of materials with excellent comprehensive functions without trade-offs between these properties.

Flexible Hard Coatings with Self-Evolution Behavior in a Low Earth Orbit Environment

Lightweight, long lifetime, and flexible polymer membrane-based structures, which are tightly folded on the ground and then unfolded in space, suffer from repeated bending before launching and fatal erosion on exposure to atomic oxygen (AO) in a low Earth orbit (LEO). Although various AO-resistant coatings have been developed, a coating that can simultaneously meet the critical requirements for the mechanical robustness and long-term protection of polymer membranes is rare. Here, we fabricated a coating with mechanical robustness and long-term space endurance, starting from an inorganic polymer precursor. A hybrid coating with a nanoscale polymer/silica bicontinuous phase is first prepared on the ground, which exhibits outstanding flexibility and excellent abrasion resistance. Then, the coating shows an in situ self-evolution behavior under AO and ultraviolet (UV) synergism to afford dense and crack-free silica coating with outstanding endurance. Our strategy displays great potential for protecting deployable membrane structures serving in the LEO.

Fabrication of ultra-smooth hybrid thin coatings towards robust, highly transparent, liquid-repellent and antismudge coatings

Liquid-repellent and anti-smudge coatings have a wide range of applications on the surface of materials. In this work, a novel liquid-repellent anti-smudge hybrid coating was in situ fabricated by using tetraethyl orthosilicate (TEOS) and dimethoxydimethylsilane (DMDEOS) under acid catalysis. The resulting coatings had a high transmittance of 3-4% higher than that of blank glass. The superior smoothness and high mobility of generated poly(dimethyl siloxane) (PDMS) chains on the surface resulted in low sliding angles of 4.5° (water) and 2.8° (n-hexadecane), and a high water sliding velocity of 15.6 cm s^-1 at a tilting angle of 70°. In addition, the hybrid coatings could repel both ink and dust contaminations and hinder bacteria adhesion. What's more, the anti-smudge coatings demonstrated excellent durability and mechanical properties of 8H pencil hardness and 5A adhesion grade. Thus, a new perspective is provided for the preparation of anti-smudge coatings. The simple preparation method would bring a breakthrough in the development and application of anti-smudge materials.

Robust Hybrid Omniphobic Surface for Stain Resistance

Inspired by natural living surfaces, researchers have developed many excellent anti-smudge coatings, but there remain some critical challenges such as complex or expensive fabrications, poor long-term stability, non-transparency, etc., which may limit their large-area application. In this work, we designed a robust and transparent omniphobic coating with a one-step dip coating method. The perfluoropolyether chains were grafted on a smooth glass surface, and the coating surface not only presented good liquid repellency and stain resistance but also owned excellent mechanical wear resistance. The stain resistance property and wettability have barely changed after hundreds of thousands of friction cycles in air or even in an organic solvent surrounding. The robust hybrid coating possesses simple preparation, an excellent property, and durability, which may bring a widespread interest in the engineering application field.

Hard yet Flexible Transparent Omniphobic GPOSS Coatings Modified with Perfluorinated Agents

Transparent materials with glasslike hardness and polymer-like flexibility are highly useful but rare. This paper reports the incorporation of the low-surface-tension pentafluoropropionic acid (FC₂-COOH) or tridecafluoroheptanoic acid (FC₆-COOH) into a 3-glycidyloxypropyl polyhedral oligomeric silsesquioxane (GPOSS) coating to yield hard/flexible omniphobic coatings. To avoid the macrophase separation of these additives from GPOSS and thus maintain the coating's high transparency, they are first reacted with excess GPOSS via the opening of the glycidyl rings with the carboxy groups to produce mixtures of GPOSS and GPOSS-FC₂ or GPOSS-FC₆. The fluorinated GPOSS mixtures are then photochemically cured. This study investigates the influence of the type and amount of a fluorinated agent used on the wetting and mechanical properties of the coatings. The wetting properties studied include surface energies, liquid sliding behavior, and repellency against an artificial fingerprint liquid. Meanwhile, the mechanical properties include pencil hardness, Young's modulus, hardness, and resistance to abrasion by steel wool and cheesecloth. Aside from producing coatings that may serve as a viable alternative for the currently used hard/flexible coatings in foldable smartphones, this paper provides guidelines for producing coatings with further improved omniphobicity and wear resistance.

POSS-based starlike hybrid helical poly(phenyl isocyanide)s: their synthesis, self-assembly, and enantioselective crystallization ability

Well-defined starlike hybrid helical poly(phenyl isocyanide)s with POSS cores were designed and synthesized, and their self-assembly behaviour and enantioselective crystallization ability were investigated.

Biomimetic Brushlike Slippery Coatings with Mechanically Robust, Self-Cleaning, and Icephobic Properties

In this work, a facile strategy was proposed to prepare a series of brushlike thermoplastic polyurethane (TPU) coatings with mechanically robust, self-cleaning, and icephobic performance. Through a simple multicomponent click reaction of thiolactone with a diamine compound and mono-ethenyl-terminated polydimethylsiloxane (mono-ethenyl-PDMS), a diol with amide groups and flexible PDMS was synthesized, and a novel TPU could be obtained productively by a reaction of isocyanate and diol. The unique chain structure endowed TPU films with ascendant self-stratifying properties. During solvent vapor annealing, flexible PDMS chains migrated and enriched to the surface while urethane linkages with a strong interaction tended to locate at the substrate. Based on this, TPU-PDMS films exhibited mechanically robust property, and the tensile strength value of TPU-PDMS-3 showed a sharp increase to 48.62 MPa. The resultant TPU-PDMS-10 coatings exhibited a water repellent behavior and possessed superior movability of droplet water, and also the dirt on it could be readily removed by rinsing with water without leaving any traces. Furthermore, three different criteria were used to characterize the icephobic performance. The coatings exhibited a significantly lower freezing point (approximately -27 °C) of supercooled water, longer delay-icing time, and less ice adhesion shear strength. Therefore, these novel brushlike TPU coatings have tremendous potential applications.

Fabrication of Robust and Transparent Slippery Coating with Hot Water Repellency, Antifouling Property, and Corrosion Resistance

Water-repellent coatings with low sliding angles for aqueous liquids are of great significance for practical applications. However, these coatings are susceptible to various types of damage during service and lose their effect. Herein, a robust and transparent slippery coating with extremely low water sliding angle was fabricated by covalently grafting polydimethylsiloxane (PDMS) brushes in a cross-linked skeleton of epoxy resin. Polyamidoamine G5.0 with 128 NH₂ end groups was used as curing agent to induce the high cross-linking of the coating and the abundant PDMS brushes being grafted into it. Because of low surface energy and high mobility of PDMS brushes, the obtained coating exhibited a slippery performance for aqueous liquids (10 μL) with a sliding angle lower than 3° and a sliding speed as high as 1.16 mm/s. Even a 10 μL water droplet with temperature of 80 °C can slide off the coating at a low sliding angle (<5°). The strong intermolecular interactions of epoxy cross-linked skeleton endowed the coating with excellent physical and chemical stability. The sliding angle of the coating had no obvious change after heating at 120 °C for 100 h and placing outdoors for 7 months. The slippery performance was not affected by thumb press, knife scratching, high-speed friction, and water of different pH values. Furthermore, because of the excellent stability, antifouling performance, and corrosion resistance, the slippery coating can be applied to a variety of substrates, which makes the robust slippery coating have real potential for practical applications.

Liquid-Repellent Films Comprising Octamethylsilsesquioxane Selected Based on Three-Dimensional Solubility Parameters

On the basis of Hansen solubility parameters (HSP), we investigated octamethylsilsesquioxane (OMS), a siloxane compound with a cage-like structure and methyl side chains, as an omniphobic substance. The HSP of OMS were determined through dissolution tests to be similar to those of polytetrafluoroethylene (PTFE), leading to the prediction that films comprising OMS should possess liquid-repellency comparable to films comprising PTFE. Indeed, an electroless-plated Ni-P film composite with OMS particles (Ni-P/OMS film) exhibited liquid-repellency comparable to or higher than that of the Ni-P film composite with PTFE particles, except toward 1-bromonaphthalene, which has a low surface free energy. Moreover, the hydrophilic influence of the Ni-P matrix was eliminated by the use of polydimethylsiloxane (PDMS) as the matrix instead of Ni-P, resulting in enhanced liquid-repellency and water-sliding behavior of the solution-sprayed PDMS film composite with the OMS particles (PDMS/OMS film). These films comprising OMS particles are promising candidates for nonfluorinated liquid-repellent films.

Organocatalyzed atom transfer radical polymerization (ATRP) using triarylsulfonium hexafluorophosphate salt (THS) as a photocatalyst

Triarylsulfonium hexafluorophosphate salt (THS), an organic and inexpensive compound, was employed as a photocatalyst for metal free atom transfer radical polymerization (ATRP) of methacrylate monomers.