|Budget Amount *help
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1999 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1998 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1997 : ¥2,100,000 (Direct Cost : ¥2,100,000)
This project studied thremoreversible gelation of associating polymers with multiple cross-link junctions. We paid special attention to (1) the multiplicity and sequence length of the network junctions, (2) motion of network junctions and the number of elastically effective chains, (3) competition between intermolecular micellization and intermolecular cross-linking, (4) effect of added surfactants, (5) cooperative effect of conformational change of polymers and gelation, (6) formation of mixed networks. We derived complete phase diagrams including phase separation, gelation, micellization, microphase separation etc. The conventional Eldridge-Ferry method is extended to evaluate multiplicity, as well as enthalpy, of the cross-links, and applied to the experimental gel melting curves of poly (vinyl alcohol) in water. The effect of added surfactants on the formation of reversible gels in hydrophobically modified polymer solutions is also studied under the assumption of the existence of a minimum multiplicity required for stable cross-links. For telechelic associating polymers, we found the condition for appearance of flower micelles (micelles formed only by loops) before the gel point.