Structural characterization of amphiphilic polymer conetworks end-linked with the optimal amount of cross-linker

Amphiphilic polymer conetworks were synthesized by the end-linking of ABA triblock copolymers using optimal (minimal) amount of cross-linker in pursuit of nanoscale phase separated materials with a long-range order. Small-angle neutron scattering (SANS) was employed to investigate the structure of the conetworks in D2O. The measurements revealed single SANS correlation peaks, indicating a short-range, liquid-like order within the conetworks, similar to that observed in counterparts prepared using super-optimal amount of cross-linker. This was attributed to the relatively low molecular weight of the chains and the constraints of end-linking. Thus, a reduced loading of cross-linker did not affect the structure of the conetworks. In contrast, the conetwork structure was significantly affected by the polymer architecture at minimal cross-linker loading, with much less intense SANS correlation peaks exhibited by the BAB triblock and the statistical copolymer end-linked conetworks, and the randomly cross-linked statistical conetwork. (C) 2009 Elsevier Ltd. All rights reserved.