Polymer Functional Nanodiamonds by Light-Induced Ligation

Abstract

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 decreas...