Ultrastable Underwater Anti-Oil Fouling Coatings from Spray Assemblies of Polyelectrolyte Grafted Silica Nanochains

Surfaces that have superhydrophilic characteristics are known to exhibit extreme oil repellency under water, which is attractive for applications including anti-fogging, water-oil separations, and self-cleaning. However, superhydrophilic surfaces can also be easily fouled and lose their extreme oil repellency, which limits their usage in practical applications. In this work, we create an anti-oil fouling coating by spray coating poly(acrylic acid) (PAA)-grafted SiO₂ nanochains (approximately 45 nm wide and 300 nm long) onto solid surfaces, forming a nanoporous film exhibiting superhydrophilicity (water contact angle in air ≈ 0°) and underwater superoleophobicity (dichloroethane contact angle ≥ 165°). The polymer-grafted nanochain assemblies exhibit extremely low contact angle hysteresis (<1°) and small adhesion hysteresis (-0.05 mN m^-1), and thus, oil can readily roll off from the surface when the coating is immersed in water. Compared to other superhydrophilic surfaces, we show that both the unique structure of spray-assembled nanochains and the hygroscopic nature of PAA are essential to enable ultrastable anti-oil fouling. Even after the PAA-grafted nanochain coating is purposely fouled by oil, oil can be readily and completely expelled and lifted-off from the coating within 10 s when placed under water. Further, we show that our coating retains underwater superoleophobicity even after being subjected to shearing under water for more than 168 h. Our approach offers a simple yet versatile method to create an ultrastable superhydrophilic and anti-oil fouling coating via a scalable manufacturing method.

Honeycomb-patterned hybrid films of surfactant-encapsulated polyoxometalates by a breath figure method and its electrocatalysis for BrO3−

Surfactant-encapsulated POMs can self-assemble into ordered porous honeycomb films under a moist atmosphere. We successfully fabricated (DODA)₁₀{Cu₄(PW₉)₂} honeycomb films by using a one-step method.

One-step fabricated wettable gradient surface for controlled directional underwater oil-droplet transport

Controlled self-propelling of the underwater oil droplet is achieved by a one-step anodic oxidation method.

Super water absorbency OMMT/PAA hydrogel materials with excellent mechanical properties

Montmorillonite/poly(acrylic acid) composite hydrogels, fabricated through UV irradiation polymerization, have a super water absorbency of 2786 g g⁻¹ and excellent mechanical properties.

Wettability and permeation of ethanol/water mixture on porous mesh surface

A serial of copper meshes with different chemical composition and roughness was prepared by modifying different mixed thiols, which showed different wetting behavior and permeation behavior for different ethanol/water mixed solution.

Polymer porous interfaces with controllable oil adhesion underwater

Porous montmorillonite (MMT)/poly acrylic acid (PAA) composite surfaces with different oil adhesions were achieved by controlling the MMT arrangement in the pore wall.