Self-assembly of fluorous amphiphilic copolymers with ionogels and surface switchable wettability

Abstract

Fluorous amphiphilic copolymers were synthesised by the microwave assisted copolymerization of 1H,1H,2H-perfluoro-1-octene and vinyl imidazole and characterized using size exclusion chromatography, FT-IR and 1 H, 13C, 19F, and DOSY NMR. The fluorous amphiphilic copolymer, when coated on a glass surface, exhibited a water contact angle (WCA) of 112°, compared to that of 67° obtained for ionic homopolymers (poly(vinylimidazolium bromide)). Switchable wettability was controlled by tuning both ionic groups and the hydrophobic fluorous segments in the amphiphilic copolymer. The fluorous ionic copolymer offered a variable WCA of 112°, 107° or 97° depending on the surface hydrophobicity of the substrate, such as glass, a compressed carbon sheet or a Teflon surface, respectively. These amphiphilic copolymers self-assembled in different solvents and swelled. The swelling was up to 966% in water and methanol and up to 2036% in DMF with fluorous anions. The micelles formed from the self-assembly of amphiphilic copolymers in different solvents were characterized by dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM). Furthermore, Ag nanoparticles were coated on the amphiphilic ionomer and characterized using scanning electron microscopy and atomic force and electrostatic force microscopy.