Thermoreversible gelation driven by polymer conformational change

5 Thermoreversible gelation driven by polymer conformational change 

Most natural polymers undergo conformational transition preceding to gelation. Activation of the particular functional groups on a polymer chain accompanied by a proper three-dimensional conformation change is a necessary prerequisite for interchain cross-linking. 

A similar two-step mechanism of gelation through coil-helix transition was confirmed for synthetic polymers with stereo-regularity. For instance, in solutions of syndiotactic poly(methyl methacrylate) (PMMA) in toluene, a fast intramolecular conformational change is followed by the intermolecular association leading eventually to gelation [49,50]. 

Other important examples are globular proteins. Proteins, such as ovalbumin and human serum albumin, are believed to form gels after some of the intramolecular bonds 

17 (a) Dissociation of intramolecular bonds, and (b) dissociation of intramolecular flower micelles, 

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