“Smart” Surfaces of Polymer Brushes

Using a continuum self-consistent field theory in real space, we have investigated the structure and response of two types of “smart” polymer brushes: (1) Poly(N-isopropyl acrylamide) (PNIPAM) brushes in water. Here with a concentration-dependent Flory-Huggins parameter obtained from experiments, we have studied the structure and thermo-response of PNIPAM brushes as a function of chain length and grafting density. (2) Charged two-component polymer brushes. Here we have studied diblock copolymer (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. We have also compared the charged DBC brushes with corresponding binary brushes. Our result can be used to guide the experimental design of “smart” surfaces from these polymer brushes.