STATIC AND DYNAMIC STRUCTURE FACTORS FOR STAR POLYMERS IN THETA-CONDITIONS

The static and dynamic structure factors for star polymers in THETA so lutions are derived for semiflexible models and the partially stretche d (PS) arm model. The PS model for the static structure factor is foun d to be in fairly good agreement with SANS experiments with exclusion of the high-k region, where only a qualitative agreement is obtained. The nonpreaveraged first cumulant for the PS model reproduces fairly w ell the peculiar effects found by neutron spin-echo experiments even t hough those experiments were carried out in good solvents. The effects of preaveraging and screening of the hydrodynamic interaction are con sidered. Results for the full dynamic structure factor are presented o nly in the preaveraging approximation.