Superamphiphobic Diblock Copolymer Coatings

A new diblock copolymer, poly[3-(triisopropyloxysily)propyl methacrylate]-block-poly[2-(perfluorooctyl)ethyl methacrylate] (P1 or PIPSMA-b-PFOEMA), that bore a fluorinated PFOEMA block and a sol gel forming PIPSMA block was synthesized by sequential anionic polymerization and was characterized. P1 was then used to coat silica particles. Factors affecting the amount of P1 grafted onto the silica particles by the sol gel reactions of the PIPSMA block were investigated, and the coating conditions were optimized. At sufficiently high P1-to-silica mass feed ratios, P1 chemically grafted onto silica surfaces to yield a monolayer. While monolayer formation was supported by results of thermogravimetric analyses, dynamic light scattering, atomic force microscopy, and transmission electron microscopy, our X-ray photoelectron spectroscopy study suggested that the monolayer was topped by the PFOEMA block. Depositing these particles onto microscope slides and printing paper yielded rugged silica films. These films were superamphiphobic, and both water and oil droplets (cooking oil, diodomethane, and hexadecane) possessed large contact angles. The films composed of P1-coated silica particles had substantial resistance to etching by aqueous NaOH solution.