Superhydrophobic surfaces from hydrophobic or hydrophilic polymers via nanophase separation or electrospinning/electrospraying

This paper explores the role of the hydrophobic or hydrophilic character of a polymer on its potential to produce superhydrophobic surfaces when processed by appropriate techniques. More precisely, porous films of poly(ethyl methacrylate) (PEMA) and polycarbonate (PC) were prepared by the electrospinning/electrospraying method while solutions of poly(methyl methacrylate) (PMMA), PEMA, PC and PEMA-PC blends were processed by nano-phase separation induced by the addition of a nonsolvent. Moreover, two fluoropolymers poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) and poly(2,2,3,3,3-pentafluoropropyl methacrylate) (PPFPMA), were treated by the latter technique. Various surface morphologies were obtained due to different fiber and/or particle size. Results demonstrated that the films produced by hydrophilic polymers via the electrospinning/electrospraying method were hydrophobic and a narrow contact angle range was observed, regardless of film thickness. On the contrary, films produced by the same polymers and their blends via phase separation, presented a wide range of contact angles, in contrast to the case of hydrophobic polymers. These films exhibited also superhydrophobic properties. Our results suggest that the detrimental role of random surface morphology on contact angle values can be counterbalanced by the inherent hydrophobicity of the polymer. (C) 2011 Elsevier B.V. All rights reserved.