SANS study of sulfonate end group effect on polystyrene self-diffusion

Film formation from a latex involves interdiffusion of polymer chains. The interdiffusion behavior of polystyrene with H ends, one sulfonate end, and two sulfonate ends are compared via small-angle neutron scattering (SANS) a nd a direct nonradiative energy transfer technique (DET) at short times. Hi gh molecular weight (M-n congruent to 300 000) anionically synthesized poly styrenes were confined in latex particles utilizing an artificial miniemuls ification technique. Interdiffusion of the polystyrenes in a latex film was carried out at temperatures of 125-145 degreesC. The diffusion coefficient s of polystyrene with H ends were five times and 10 times higher than that of polystyrene with one sulfonate end and two sulfonate ends, respectively. The probable cause is end-to-end aggregation of the chains, supported by t he ratio Rg/M-1/2 remaining substantially constant.