Closed-loop phase behavior and baroplasticity of deuterated polystyrene-block-poly(n-pentyl methacrylate) copolymer investigated by SANS and FTIR spectroscopy

Abstract

The closed-loop phase behavior of deuterated polystyrene-block-poly(n-pentyl methacrylate) copolymer (dPS-PnPMA) was investigated by small-angle neutron scattering (SANS) and temperature-dependent Fourier transform infrared (FT-IR) spectroscopy. The effect of hydrostatic pressure on the transition temperatures was studied by using SANS. We found that dPS-PnPMA has large pressure coefficients of transition temperatures (dT/dP= +/- 725 degrees C/kbar). Since this block copolymer exhibited excellent baroplastic property, it was easily molded into a desirable shape at a relatively low temperature under medium pressure. On the other hand, commercially available polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene copolymers were not molded at the same processing condition. Finally, we investigated the driving force inducing the closed-loop phase behavior by using temperature-dependent FT-IR.