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) and a direct nonradiative energy transfer technique (DET) at short times. High molecular weight (M n ≅ 300 000) anionically synthesized polystyrenes were confined in latex particles utilizing an artificial miniemulsification technique. Interdiffusion of the polystyrenes in a latex film was carried out at temperatures of 125−145 °C. The diffusion coefficients 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 the ratio R g/M 1/2 remaining substantially constant.