Novel amphiphilic triblocks fitted with photocrosslinkable termini, and their photocrosslinking to conetworks

Two new telechelic amphiphilic triblock copolymers, HE3-PEG-b-PDMS-b-PEG-HE3 and HE3-PEG-b-PDMS-b-PEG-HE3, i.e., sequence-reversed triblocks of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic polydimethylsiloxane (PDMS) segments fitted with photocrosslinkable tri[2-(3,4-cyclohexane oxide)ethyl-dimethylsiloxy]silane (HE3) termini, were synthesized, characterized, photocrosslinked to amphiphilic conetworks (APCNs), and the properties of the APCNs were analyzed. APCNs in which the crosslinking sites are located in the hydrophobic domains exhibited significantly better mechanical properties than those in which the crosslinks were in the hydrophilic domains. The stiff domains formed of the UV-crosslinkable HE3 chain-end substituents provide not only crosslinking but reinforcement as well. The crosslinking/reinforcement efficiency was greatly enhanced by the addition of excess HE3. Water-swollen APCNs were optically clear and exhibited mechanical properties appropriate for biomedical application. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 174–185, 2008