We present a systematic study on the effect of overall grafting density on the 'rippled' nanostructure formed by mixed poly(tert-butyl acrylate)/polystyrene brushes on silica particles. The mixed brushes with molecular weights of ~ 23 kDa for both polymers were synthesized by sequential surface-initiated atom transfer radical polymerization and nitroxide-mediated polymerization from asymmetric difunctional initiator (Y-initiator)-functionalized silica particles. By changing the mass ratio of Y-initiator to silica particles in the initiator immobilization step, we found that the overall grafting density of mixed brushes can be systematically tuned while the individual grafting densities of two polymers remained comparable. Transmission electron microscopy studies showed that the ripple wavelength of the nanopattern formed from lateral microphase separation of mixed brushes increased with decreasing the grafting density, and the normalized ripple wavelength scaled with -0.47 power of overall grafting density in the range of 1.06 to 0.54 chains/nm2.

Grafting density effect on morphology of mixed homopolymer brushes on silica particles

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.