Long-range order in physical networks of gel-forming triblock copolymer solutions

Structural studies on physical gels, based on a triblock copolymer and solvent selective for its midblocks, are presented. Gel formation in such systems arises due to interconnected microdomains that form the junctions in a three-dimensional network. Small angle X-ray scattering studies revealed that the physical networks show either short-range order, described by an effective hard sphere model, or long-range order, where junctions are arranged on a cubic lattice. The emerging morphology depends on the thermal conditions during preparation of such systems, which essentially reflects a competition among microdomain ordering and formation of the physical network.