Durable superamphiphobic coatings with high static and dynamic repellency towards liquids with low surface tension and high viscosity

Robust Superamphiphobic Coating Applied to Grease-Proof Mining Transformer Components

The iron core and heat sink in a mining transformer are susceptible to damage from oil spills or the harsh mine environment; the deterioration of oil products in the underground environment and transformers produce massive amounts of harmful liquid substances, which may lead to unnecessary economic losses in drilling engineering. To overcome this issue, a convenient and economical way to protect transformer components was developed. Herein, we proposed an air spray technology at room temperature for the preparation of antigreasy superamphiphobic coatings, which are suitable for bulk metallic glass transformer cores and ST13 heat sinks. The addition of polypyrrole powder effectively improves the thermal conductivity and specific heat of the coating in the range of 50-70 °C. More importantly, the fabricated coating has excellent repellency to liquids, such as water, ethylene glycerol, hexadecane, and rapeseed oil. Meanwhile, the coating has excellent physical and chemical resistance and outstanding antifouling features, which provide a feasible solution for combating grease pollution and corrosion in the mine environment. Taking multifaceted stability into consideration, this work contributes to enhancing the application of superamphiphobic coatings in the fields of protecting transformer components in the harsh environment or during transformer operation faults.

Dynamic electrostatic assembly of polyelectrolytes and perfluorosurfactants into environmentally Adaptable, freestanding membranes with ultralow surface energy and surface adhesion

HYPOTHESIS

Integration of ultralow surface energy and surface functionality on one surface coatings is highly desirable in chemical and biomedical applications. However, it is a fundamental challenge to reduce surface energy without cost of surface functionality and vice versa. To address this challenge, the present work made use of the rapid and reversible change of surface orientation conformations of weak polyelectrolyte multilayers to create ionic, perfluorinated surfaces.

EXPERIMENTS

Poly(allylamine hydrochloride) (PAH) chains and the micelles of sodium perfluorooctanoate (SPFO) were layer-by-layer (LbL) assembled into (SPFO/PAH)_n multilayer films, which readily exfoliated to freestanding membranes. The static and dynamic surface wetting behaviors of the resulting membranes were studied by sessile drop technique and their surface charge behaviors in water by electrokinetic analysis.

FINDINGS

As-prepared (SPFO/PAH)_n membranes exhibited ultralow surface energy in air; the lowest surface energy is 2.6 ± 0.5 mJ/m² for PAH-capped surfaces and 7.0 ± 0.9 mJ/m² for SPFO-capped surfaces. They readily became positively charged in water, which allowed not only effective adsorption of ionic species for further functionalization with subtle change in surface energy, but effective adhesion onto various solid substrates such as glass, stainless steel, and polytetrafluoroethylene to endorse the wide applicability of (SPFO/PAH)_n membranes.

Durable and transparent super anti-wetting coatings with excellent liquid repellency and anti-fouling performance based on fluorinated polysiloxane

Super anti-fouling coatings are of great interest because of their good liquid repellency and anti-fouling performance. However, it is challenging to prepare durable and transparent super anti-fouling coatings, especially via...

Robust and durable liquid-repellent surfaces

This review provides a comprehensive summary of characterization, design, fabrication, and application of robust and durable liquid-repellent surfaces.

One-step fabrication of robust and durable superamphiphobic, self-cleaning surface for outdoor and in situ application on building substrates

HYPOTHESIS

Water and oil inhibition treatment is essential for protecting natural and artificial stone surfaces. Bioinspired super-antiwetting surfaces with "lotus effect", together with superoleophobic properties, can be achieved combining very low-surface-energy materials and suitable surface roughness. Exploiting the natural roughness of stone surfaces, the simple and inexpensive fabrication of superamphiphobic surfaces through the coating dispersion deposition is expected. It seems the ideal method for the safeguard of contemporary and historical constructions, since the physical, chemical and aesthetic properties can be maintained.

EXPERIMENTS

The new coating agent (3-perfluroether-amidopropylsilane) was synthesized via one-step amidation. Hydrophobicity, robustness and environmental durability were systematically studied on stone surfaces through several tests: contact angle (CA), contact angle hysteresis (CAH), water inhibition efficiency, vapor diffusivity, chemical and mechanical resistance, artificial and field-exposure ageing.

FINDINGS

The as-prepared coating demonstrated superamphiphobicity (oil and water CA > 150° with CAH < 10°) on stones with low and high porosity. Moreover, it manifested very high water inhibition efficacy while maintaining high vapor diffusivity and aesthetic properties of substrates. The superhydrophobic coating showed good robustness towards corrosive chemical agents, peeling, mechanical abrasion, water immersion and environmental weathering, thereby permitting various outdoor applications, including stone protection in rainy regions where acid rain is also present.