Perpustakaan Digital ITB

Surfaces that have superhydrophilic character-istics are known to exhibit extreme oil repellency under water,which is attractive for applications including anti-fogging,water?oil separations, and self-cleaning. However, super-hydrophilic surfaces can also be easily fouled and lose theirextreme oil repellency, which limits their usage in practicalapplications. In this work, we create an anti-oil fouling coatingby spray coating poly(acrylic acid) (PAA)-grafted SiO2nanochains (approximately 45 nm wide and 300 nm long)onto solid surfaces, forming a nanoporousfilm exhibitingsuperhydrophilicity (water contact angle in air?0°) andunderwater superoleophobicity (dichloroethane contact angle?165°). The polymer-grafted nanochain assemblies exhibitextremely low contact angle hysteresis (<1°) and small adhesion hysteresis (?0.05 mN m?1), and thus, oil can readily roll offfrom the surface when the coating is immersed in water. Compared to other superhydrophilic surfaces, we show that both theunique structure of spray-assembled nanochains and the hygroscopic nature of PAA are essential to enable ultrastable anti-oilfouling. Even after the PAA-grafted nanochain coating is purposely fouled by oil, oil can be readily and completely expelled andlifted-offfrom the coating within 10 s when placed under water. Further, we show that our coating retains underwatersuperoleophobicity even after being subjected to shearing under water for more than 168 h. Our approach offers a simple yetversatile method to create an ultrastable superhydrophilic and anti-oil fouling coating via a scalable manufacturing method.