Structure and response of “smart” polymer brushes

PMSE 65

Qiang Wang, q.wang@colostate.edu, Department of Chemical and Biological Engineering, Colorado State University, 1370 Campus Delivery, Fort Collins, CO 80523
Using a continuum self-consistent field theory in real space, we have studied the structure and stimuli-response of three smart polymer brushes: (1) Thermo-response of grafted poly(N-isopropyl acrylamide) (PNIPAM) in water. Here we use a concentration-dependent Flory-Huggins parameter obtained from experiments, and have studied the structure and thermo-response of PNIPAM brushes as a function of chain length and grafting density. (2) Solvent-response of uncharged diblock copolymer (DBC) brushes. Here we have studied the effects of copolymer chain length, copolymer composition (length ratio of the two blocks), grafting density, and A-B incompatibility on the brush height and surface switchability of DBC brushes. (3) Stimuli-response of charged two-component polymer brushes. Here we have further studied DBC brushes with one block charged. When charge effects dominate, it is ineffective to switch the brush surface by different solvents. Rather, applied electric field and solution pH are more effective, with sharp transitions for the surface-switching.