IN-SITU FORMATION OF POLYSTYRENE IN ADSORBED SURFACTANT BILAYERS ON PRECIPITATED SILICA

Surfactant bilayers adsorbed on silica are used as the reaction site f or the formation of ultrathin polymer films from coadsorbed or adsolub ilized monomer. Results from the polymerization of styrene in cetyltri methylammonium bromide (CTAB), in octylphenoxypoly(ethoxy)ethanol, and in methyltri(C8-C10)ammonium chloride bilayers show effective convers ion of adsolubilized styrene monomer to polystyrene. The process has b een demonstrated effective with amorphous precipitated silica substrat es having a variety of surface areas and with two types of initiation schemes. The extractable polymer has been characterized using photoaco ustic FTIR, UV, and gel permeation chromatography (GPC). Only approxim ately 25% of the polymer was extractable after refluxing for 4 h in te trahydrofuran. The impact of the treatment on some industrially import ant surface properties of the modified silicas has also been determine d. The process offers a potentially inexpensive method for modifying c hemical and physical surface properties of various substrates.