Wettability adjustment of PVDF surfaces by combining radiation-induced grafting of (2,3,4,5,6)-pentafluorostyrene and subsequent chemoselective "click-type" reaction

A novel strategy combining (2,3,4,5,6)-pentafluorostyrene (PFS) grafting and subsequent wthiol/parafluorine "click" type post-grafting modification is presented to impart specific surface properties to bulky PVDF samples. First, PFS was radiation-induced grafted on the surface of PVDF using gamma-rays as the radiation source, and both pre-irradiation and simultaneous irradiation techniques were attempted. The extent of modification was higher with the latter strategy, as determined by semi-quantitative ATR-FT1R analyses. Subsequent coupling was then undertaken using 3-mercapto-1,2-propanediol (MPD). The chemoselective functionalization was qualitatively and semi-quantitatively evidenced by ATR-FTIR, and led to PVDF-g-PPFS decorated with hydroxyl groups. The resulting surface properties were investigated by wettability measurements, and hysteresis with water and contact angle with acetonitrile both evidenced the successful and appropriate modification. This strategy opens the scope of a new means to modify both swelling and surface properties of PVDF samples, as required for specific applications (such as separator in electrochemical devices or in pipe systems for handling specific chemicals). (C) 2014 Elsevier Ltd. All rights reserved.