Supramolecular X- and H-shaped star block copolymers via cyclodextrin-driven supramolecular self-assembly

Abstract

A wide variety of novel complex macromolecular X- and H-shaped star block copolymers based on supramolecular cyclodextrin (CD)/adamantane interactions are reported. Mid-chain adamantyl poly(N,N-dimethylacrylamide) (PDMA; M_n = 12 000 g mol⁻¹, Đ = 1.10), poly(N,N-diethylacrylamide) (PDEA; M_n = 5400 g mol⁻¹, Đ = 1.08) and P(DEA-b-DMA) (M_n = 10 400 g mol⁻¹, Đ = 1.13) as well as double adamantyl end functionalized PDMA (M_n = 6400 g mol⁻¹, Đ = 1.06) and PDEA (M_n = 6800 g mol⁻¹, Đ = 1.11) are synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. Furthermore, mid-chain β-CD functionalized PDMA (M_n = 10 200 g mol⁻¹, Đ = 1.26), PDEA (M_n = 11 100 g mol⁻¹, Đ = 1.30) and P(DEA-b-DMA) (M_n = 7600 g mol⁻¹, Đ = 1.26) are synthesized via a combination of RAFT polymerization and copper(I) catalyzed azide alkyne cycloaddition. Subsequently, the formation of the target architectures via supramolecular association of CD- and adamantyl-functionalized building blocks is evidenced via nuclear Overhauser enhancement spectroscopy and dynamic light scattering. Furthermore, the temperature responsive behavior of the formed star block copolymers is investigated.