Covalently tethered comb‐like polymer brushes on hydrogen‐terminated Si (100) surface via consecutive aqueous atom transfer radical polymerization of methacrylates

Abstract

AbstractThe hydrogen‐terminated Si (100) (SiH surface) was functionalized by coupling with 4‐vinylbenzyl chloride (VBC) to form a SiVBC surface, which serves as macroinitiators for the surface‐initiated aqueous atom transfer radical polymerization (ATRP) of 2‐hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol)methacrylate (PEGMA) to prepare SiVBCgPHEMA and SiVBCgPPEGMA substrates, respectively. The ellipsometric results revealed that the surface‐initiated ATRP of both PHEMA and PPEGMA brushes proceeded in a controlled fashion. By adjusting the monomer concentration, an eccentric polymer thickness dependence on the initial monomer concentration [M]0 was observed for both HEMA and PEGMA, i.e., in the dilute regime, the thickness of the polymer film increases with the increase in [M]0; however, beyond critical [M]0, the thickness deceases gradually with the further increase. Such an eccentricity was tentatively correlated to the counteractive combination of the increase in [M]0 and decrease in the apparent polymerization rate constant. Both SiVBCgPHEMA and SiVBCgPPEGMA substrates were esterified for the subsequent surface‐initiated ATRP, resulting in corresponding comb‐like brushes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2590–2599, 2006