End-linked, amphiphilic, degradable polymer conetworks: Synthesis by sequential atom transfer radical polymerization using a bifunctional, cleavable initiator

Abstract

End-linked, degradable, amphiphilic polymer conetworks (APCNs) of various compositions and architectures were synthesized by sequential atom transfer radical terpolymerization of monomers and cross-linker using a cleavable, bifunctional initiator, bearing two acid-labile hemiacetal ester groups. The incorporation of the initiator residue into the conetworks rendered them cleavable in the middle of their elastic polymer chains. The temporal evolution of the swollen mass of the conetworks in acidified THF-water mixtures was studied and it was determined that the APCN hydrolysis rates were dependent on both conetwork composition and architecture. Regarding the former, hydrophobic APCNs degraded slowly or they even did not dissolve at all. Regarding the latter, conetworks with hydrophobic monomer and hydrophobic cross-linker units distributed around the initiator fragment also dissolved more slowly or they did not degrade at all. Finally, characterization of the star copolymers, produced from conetwork hydrolysis, allowed the determination of the APCN core functionality to be around 30.