SURFACE-TOPOGRAPHY AND COMPOSITION OF DEUTERATED POLYSTYRENE-POLY(BROMOSTYRENE) BLENDS

Surface structure, obtained from atomic force microscopy and X-ray ref lectivity, and surface chemical analysis data, obtained from X-ray pho toelectron and static secondary ion mass spectroscopy, are reported fo r blends of poly (p-bromostyrene) with poly(deuteriostyrene). When hig h speeds are used in the spin-coating process, the atomic force micros copy measurements reveal that the surface structure consists of island s, the distribution and number changing with the poly(bromostyrene) co ntent. A ribbon structure is observed at just above 50% (w/w) poly(bro mostyrene) in the mixture. These ribbons merge to form more continuous structures, leaving voids at higher concentrations. X-ray reflectivit y data from the films were consistent with the topographical features observed with the AFM. At low spinning speeds, continuous films with l ittle or no topographical structure are formed. The islands observed a t high spinning speeds are predominately poly(bromostyrene) and reflec t the importance of thermodynamic and kinetic driving forces in their formation.