Isotope effect on elution behavior of block copolymers in temperature gradient interaction chromatography

Abstract

Interaction chromatography (IC), first developed by professor Chang and his coworker, is a big contribution to polymer characterization community. In IC, it is general believe that the smaller polymer molecules which less interact with stationary phase is eluted earlier than the larger ones which more strongly interact with stationary phase. However, in the case of PS comb (h-PS backbone, d-PS branch), the polymer having larger molecular weight was eluted earlier than the one with smaller molecular weight although they were still in IC region. The study is an effort to elucidate the reason behind the peculiar phenomenon.In chapter 1, HPLC methods for polymer characterization and two model of temperature gradient interaction chromatography (one is used to simulate the retention behavior of comb-shaped polystyrene) was introduced In chapter 2, the simulation of retention behavior of two comb-shaped polystyrene (d-PS backbone, h-PS branches and h-PS backbone, d-PS branches) was presented. In order to determine the experimental coefficient, van’t Hoff plot for linear d-PS and h-PS was implemented. The simulated retention behavior of PS comb is compared with the experimental data from previous study.In chapter 3, with the purpose to elucidate the peculiar phenomenon of PS comb, retention behavior of diblock copolymer hydrogenous polystyrene-b-deuterated polystyrene (hPS-b-dPS) was systematically investigated by altering the temperature and column. hPS-b-dPS changed its retention behavior, from increasing order of MW to decreasing order of MW in IC region when temperature was varied. Pore size of column plays an important role in the phenomenon.