Preparation of a durable superhydrophobic membrane by electrospinning poly (vinylidene fluoride) (PVDF) mixed with epoxy-siloxane modified SiO2 nanoparticles: A possible route to superhydrophobic surfaces with low water sliding angle and high water contact angle

A durable superhydrophobic surface with low water sliding angle (SA) and high water contact angle (CA) was obtained by electrospinning poly (vinylidene fluoride) (PVDF) which was mixed with epoxy-siloxane modified SiO2 nanoparticles. To increase the roughness, modified SiO2 nanoparticles were introduced into PVDF precursor solution. Then in the electrospinning process, nano-sized SiO2 particles irregularly inlayed (it could also be regard as self-assembly) in the surface of the micro-sized PVDF mini-islands so as to form a dual-scale structure. This structure was responsible for the superhydrophobicity and self-cleaning property. In addition, epoxy-siloxane copolymer was used to modify the surface of SiO2 nanoparticles so that the SiO2 nanoparticles could stick to the surface of the micro-sized PVDF mini-islands. Through the underwater immersion test, the SiO2 nanoparticles cannot be separated from PVDF easily so as to achieve the effect of durability. We chiefly explore the surface wettability and the relationship between the mass ratio of modified SiO2 nanoparticles/PVDF and the CA, SA of electrospun mat. As the content of modified SiO2 nanoparticles increased, the value of CA increased, ranging from 145.6 degrees to 161.2 degrees, and the water SA decreased to 2.17 degrees, apparently indicating that the membrane we fabricated has a perfect effect of superhydrophobicity. (C) 2011 Elsevier Inc. All rights reserved.