Abstract
A new method of surface modification based on the "grafting from" polymerization process enabled to prepare original silica nanoparticles covered with PDVF "hair". This strategy involved two steps: (i) the radical addition of 1,4-diiodoperfluorobutane initiated by tert-butylperoxypivalate onto the double bonds of silica nanoparticles (specific area of 150 m2 g 1) led to silica that bore C4F8I end-groups on its surface, and (ii) its use as original macrochain transfer agent in the "grafting from" polymerization of vinylidene fluoride (VDF) initiated by bis(4-tert-butylcyclohexyl) peroxydicarbonate. The characterizations of both modified silica were achieved by elemental analysis, 1Hand 19F magic angle spinning solid state rotationalecho double resonanceNMRspectroscopy, thermogravimetry, and water contact angle (WCA) assessments. The grafting efficiency was confirmed by three features: (i) the increase of weight percentage of fluorine atom (that ranged from 0 for the starting unsaturated silica to 2.50% for silica-bearing -C4F8I end-group and to 3.32% for original silica-PVDF core-shells), (ii) a high thermostability (that reached more than 400 °C under air), and (iii) a good hydrophobicity: the WCA values were ranging from 84° to 109 ° and to 126° for vinyl silica, for silica coated with -C4F8I, and for PVDF-covered silica nanoparticles, respectively.