Fabrication of self‐cleaning poly(vinylidene fluoride) membrane with micro/nanoscaled two‐tier roughness

Based on the “lotus effect” principle, smooth microreliefs of polyvinylidene fluoride (PVDF) membrane were prepared via thermally induced phase separation process. Hydroxyl groups were introduced into PVDF membrane by pretreatment with KOH/alcohol solution. Subsequently, these hydroxyl groups grafted with (CH₃)₂SiCl₂/CH₃SiCl₃ to form nano‐clusters, which were decorated on the microreliefs of PVDF membrane. Scanning Electronic Microscopy (SEM) and Atomic Force Microscope (AFM) analysis showed the micro‐ and nano‐scale structures, similar to lotus leaf, were successfully fabricated on the PVDF membrane surface. The water contact angle and sliding angle on the fabricated lotus‐leaf‐like PVDF membrane surface were 154 and 4°, respectively. Self‐cleaning test indicated that the lotus‐leaf‐like surface of PVDF membrane has excellent superhydrophobic and self‐cleaning properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011