Fluorine-Free Super-Liquid-Repellent Surfaces: Pushing the Limits of PDMS

Abstract

Methods for fabricating super-liquid-repellent surfaces have typically relied on perfluoroalkyl substances. However, growing concerns about the environmental and health effects of perfluorinated compounds have caused increased interest in fluorine-free alternatives. Polydimethylsiloxane (PDMS) is most promising. In contrast to fluorinated surfaces, PDMS-coated surfaces showed only superhydrophobicity. This raises the question whether the poor liquid repellency is caused by PDMS interacting with the probe liquid or whether it results from inappropriate surface morphology. Here, we demonstrate that a welldesigned two-tier structure consisting of silicon dioxide nanoparticles combined with surface-tethered PDMS chains allows superliquid-repellency toward a range of low surface tension liquids. Drops of water−ethanol solutions with surface tensions as low as 31.0 mN m −1 easily roll and bounce off optimized surface structures. Friction force measurements demonstrate excellent surface homogeneity and easy mobility of drops. Our work shows that fluorine-free super-liquid-repellent surfaces can be achieved using scalable fabrication methods and environmentally friendly surface functionalization.

Dynamics of Droplets Moving on Lubricated Polymer Brushes

“…Glass slides (24 × 60 mm 2 , 170 ± 5 μm thickness, Menzel−Glaser) were coated with PDMS pseudobrushes, using the "grafting-from" 78 and the "grafting-to" 35 approaches. In short, grafting-from implies the polymerization of vaporous monomers from grafting sites on the surface while prepolymerized chains are grafted-to grafting sites.…”

Preparation of multifunctional ceramic foams for sound absorption, waterproofing, and antibacterial applications

“…Furthermore, to provide materials with waterproof properties, the grafting of polydimethylsiloxane (PDMS) or fluorine-containing chains is generally adopted because of their low surface energy. 26–31 Notably, fluorine-containing compounds generally possess a lower surface energy than PDMS, indicating a better waterproof performance. In addition, previous reports have revealed that various liquids can slide off on fluorine-modified rough surfaces, whereas, oily liquids would compromise the waterproof property of PDMS-modified rough surfaces, suggesting that fluorine-modified porous materials are more suitable for applications in harsh conditions.…”

Multifunctional Superamphiphobic Coating Based on Fluorinated TiO2 toward Effective Anti-Corrosion

“…The application of superhydrophobic coatings in oil-contaminated environments is restricted since these coatings, even with basic micro-and nano-rough structures, are frequently unable to repel oil and other liquids with a surface energy lower than water [20,21]. In order to expand the coating's wettability resistance from water to oil, the concept of superamphiphobic surfaces has emerged, i.e., the contact angle of both water and oil is greater than 150 • , and the sliding angle of both water and oil is less than 10 • [22][23][24]. and the generally accepted prerequisites for the development of superamphiphobic surfaces-that is, materials with extremely low surface energy and specifically designed surface structures [20], like kangaroo, overhanging [13], and re-entrant structures [25,26]-have been established.…”