A Well-Defined Amphiphilic Polymer Conetwork from Sequence Control of the Cross-Linking in Polymer Chains

Abstract

Well-defined amphiphilic polymer conetworks with precisely controlled number and position of cross-links were prepared by copper-catalyzed azide–alkyne cycloaddition (CuAAC) using linear polystyrene (PS) and poly(ethylene glycol) (PEG) as the building blocks. In this approach, linear polystyrene containing a specific number of bromo groups at a predetermined position of polymer chains was synthesized by multistep reversible addition–fragmentation chain transfer polymerization and chain extension using styrene and N-bromopropyl maleimide (PBMI) as the monomers. Subsequently, the bromo groups were transformed into the azido moieties via nucleophilic substitution. The well-defined linear multialkynyl PEG was prepared from PEG diglycidyl ether and propargylamine via epoxy-amine chain extension. The as-prepared PS–PEG amphiphilic polymer conetworks showed unique hydrophilic and hydrophobic phase separation with a variable swelling capacity and rheological behavior in both polar and nonpolar solvents and exhibited excellent mechanical properties with increased cross-linking density.