Synthesis and Characterization of Polyrotaxanes Comprising γ-CDs and Distal Azide-Terminated PHEMA Using Propargylamine Monosubstituted β-CDs as End Stoppers

To highlight whether γ-cyclodextrins (CDs) facilitate propargylamine monosubstituted β-CDs (PA-β-CDs) as end stoppers to get threaded onto a distal azide terminated poly(2-hydroxyethylmethacrylate) (PHEMA) homopolymer (PH-46-2N₃) to create linear and hyperbranched polyrotaxanes (PRs) via the in situ copper-catalyzed azide/alkyne cycloaddition (CuAAC), PH-46-2N₃ is self-assembled with a varying amount of γ-CDs in water and then subjected the CuAAC with PA-β-CDs to end-cap the resulting γ-CD-PHEMA polypseudorotaxanes (PPRs) into the γ-CD-PHEMA PRs. It demonstrates that γ-CDs cannot promote PA-β-CDs to be entrapped on the PHEMA chain most likely due to their different cavity size and molecular framework and linear PRs are always formed with up to 29% γ-CD coverage ratio along the PHEMA axis thereof.