Controlled grafting of a well-defined polymer on a porous glass filter by surface-initiated atom transfer radical polymerization

The atom transfer radical polymerization (ATRP) technique using the copper halide/sparteine complexes was applied to the graft polymerization of methyl methacrylate on a porous glass filter on which the initiator, 2-(4-chlorosulfonylphenyl) ethyltrichlorosilane, was immobilized by chemisorption. The graft chains were cleaved from the glass filter by the HF treatment in the presence of a phase transfer catalyst. Gel permeation chromatographic and infrared absorption spectroscopic measurements confirmed that the polymerization carried out in the presence of the free (sacrificing) initiator, p-toluenesulfonyl chloride, afforded a graft layer of well-controlled, low-polydispersity polymer on the inner surface of the porous glass filter. The number-average molecular weight (Mn) of the graft polymer increased with reaction time, and it was nearly equal to the Mn of the free polymer produced in the solution. The graft density on the inner surface of the porous glass filter was as high as those formed on a silicon wafer and a silica particle under similar conditions.