Structure and Dynamics of Terminally Attached, Swollen Block Copolymers

In this work, we report studies of the dynamics of these swollen polymer systems on silica in the presence of different solvents with the use of deuterium NMR relaxation times on specifically deuterated polymers. Of special interest is the determination of how the dynamics of the swollen styrene segments are a function of the solvent system used. To interpret these results, we have used the Hall-Helfand (HH) model for interpreting the NMR relaxation time data in terms of rates of molecular motion. We show that terminally attached polymers on surfaces behave rather differently than those in solution. Styrene segments appear to be less restricted on the surface when swollen with toluene than in solution at similar concentrations. This is not found when poorer solvents are used. Our results suggest that the motional dynamics of adsorbed polymers need additional theoretical considerations