Abstract: In this paper, we report quantitative determination of interphase thickness and domain size in poly (styrene)-block-poly (butadiene) and poly (styrene)-block-poly (butadine)-block-poly (styrene) copolymers (PS-PB and PS-PB-PS) by novel solid-state NMR methods developed recently in our group. It was found that the block copolymers having equal polystyrene (PS) weight fractions (32.5%) and different block structures have the same interphase thickness (d_itp). These experimental results were in agreement with theoretical prediction of the interphase thickness in polymer blends made by Helfand using SCFT theory.

Key words: solid-state NMR, block copolymer, interphase, domain size