Polyrotaxanes created by end-capping polypseudorotaxanes self-assembled from β-CDs with distal azide terminated PHEMA using propargylamine monosubstituted β-CDs

Abstract

When a distal azide terminated poly(2-hydroxyethylmethacrylate) (PHEMA) underwent aqueous CuAAC with propargylamine monosubstituted β-CDs (PA-β-CDs), the corresponding β-CD end-capped PHEMA was invariably generated. If it was self-assembled with varying numbers of β-CDs in water, followed by in situ CuAAC with increasing amounts of PA-β-CDs, linear polyrotaxanes (PRs) or a mixture of linear and hyper-branched PRs were created. Apparently β-CDs are able to self-assemble with an evidently unfitting PHEMA, and the entrapped β-CDs can promote part of the PA-β-CDs to be inserted into them and then to be concomitantly threaded onto the polymeric back-bone giving hyperbranched PRs after the click reaction.