文摘
A light-triggered strategy to functionalize nanodiamonds (NDs) with well-defined functional polymers is presented. The employed grafting approach is based on o-methylbenzaldehydes, which upon UV irradiation form o-quinodimethanes that undergo Diels–Alder reactions with dienophiles. A series of well-defined maleimide end-group functional polymers, i.e., poly(styrene) (Mn = 5800 g mol–1; Đ = 1.2), poly(N-isopropylacrylamide) (Mn = 5800 g mol–1, Đ = 1.2), and poly(2-(2′,3′,4′,6′-tetra-O-acetyl-α-d-mannosyloxy)ethyl methacrylate) (Mn = 24 300, 39 000, and 58 800 g mol–1, Đ ≤ 1.3), were prepared via reversible addition–fragmentation chain transfer (RAFT) polymerization of protected maleimide functional RAFT agents. After deprotection of the furan-protected maleimide end groups, the polymers were photografted to o-methylbenzaldehyde functional NDs and characterized in detail via infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The grafting density decreases with increasing polymer chain length (6.9–3.8 μmol g–1). Moreover, the binding of the glycopolymer functional NDs to the lectin Concanavalin A was demonstrated with a turbidity assay.