SYNTHESIS STRATEGIES AND PROPERTIES OF SMART AMPHIPHILIC NETWORKS

This paper briefly surveys recent developments in the field of amphiph ilic networks (APN) which are a new class of crosslinked polymer syste ms consisting of covalently bonded hydrophobic and hydrophilic chain s egments. The covalent bonds between immiscible hydrophobic and hydroph ilic polymer chains prevent demixing and yield polymer networks with u nique structure and properties. Telechelic macromonomers provide the b asis for the first generation of APNs obtained by copolymerization of the macromonomer with selected low molecular weight monomers. Synthesi s of a variety of APNs using methacrylate-telechelic polyisobutylene ( PIB) macromonomers prepared by living carbocationic polymerization (LC CP) and quantitative chain end derivatization is reviewed. The second generation of PIB-based amphiphilic networks is prepared by crosslinki ng of well-defined hydroxy-telechelic PIB and partially deprotected si lylated poly(2-hydroxyethyl methacrylate) (PHEMA) precursor chains. Ot her opportunities providing better structural control of APNs by cross linking of functional amphiphilic block copolymers (or precursors) obt ained by combining living carbocationic and anionic polymerizations ar e outlined as well. Properties of APNs, such as control of swellabilit y by composition, pH-response of swelling, fast surface structure reor ganization by contacting with solvent, morphology, sustained release o f drugs and bio- and blood compatibility, are also summarized.