Synthesis and Surface Formation of Three-Component Graft Copolymers

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The present study has aimed to obtain new insights for the environmental response behavior, unique to flexible polymer materials surfaces. The precise design with respects to the segment topology of multicomponent polymer molecule is a prerequisite for unprecedented functions required in advanced application fields from bioengineering to tribology.We have first examined on the surface formation and environmental response behavior on three-component copolymer systems. Thus we have synthesized PVA (polyvinyl alcohol) and PU (polyurethane) -based three-component systems, i.e.PVA or PU as the main chain segment and PS (polystirene) -block-PDMS (polydimethylsiloxane) as a graft segment, in which the geometrical arrangement of the three segments is inverse to the order of their surface energies, i.e.PVA (orPU) >PS>PDMS.The surface formed under the influence of the two conflicting driving forces exhibited unique environmental response by the change of the contacting medium from air to water.We have also designed a new polymer reaction process by making use of self-assembly principle in order to pre-organize macromolecular components, and subsequently converting them into permanent polymer arcitectures. Thus a unique feature, i.e.electrostatic self-assembly and subsequent covalent fixation capability, of the pyrrolidinium salt end groups has been applied for the preparation of topologically-unique, branched polymers, ring polymers and network polymers. The simple coprecipitation of the monofunctional telechelics having a cyclic onium salt group with plurifunctional carboxylates of appropriate nucleophilic reactivities has been carried out to produce the corresponding star- and comb-shaped polymers, and that of bifunctional telechelics with bifunctional carboxylate leading to the ring polymers in a diluted solution as well as the chain-extended "segmented" polymers and "model-network" polymers in a condensed phase, respectively.