Surface molecular motion of hyperbranched polystyrene and its application as a surface modifier

Well-defined hyperbranched polystyrene (HB-PS) was synthesized combining cationic and anionic polymerizations. Lateral force microscopy revealed that the glass transition temperature T _g at the surface of HB-PS was lower than the corresponding bulk value, and that the extent was dependent on the number of branching, namely the chain end concentration. Then, mixtures of HB-PS and linear PS were prepared. The surface and interfacial segregations of HB-PS were confirmed by secondary ion mass spectrometry in conjunction with neutron reflectivity. The result was in good accordance with a prediction by a self-consistent field calculation. Finally, it was concluded that the surface physical properties would be controlled by an addition of a little amount of HB-PS into PS.