Orthogonal Click Postfunctionalization of Alternating Copolymers Prepared by Nitroxide-Mediated Polymerization

Tesch M, Kudruk S, Letzel M, Studer A

Abstract

Nitroxide-mediated polymerization (NMP) was applied to prepare alternating copolymers using 1,1,1,3,3,3-hexafluoroisopropyl acrylate (HFIPA) 1 and ((6-trimethylsilyl)-hex-5-yn-1-yl)vinyl ether (THVE) 2 as monomers. The alternating sequence of the resulting poly(HFIPA-alt-THVE) 3 was proved by using tandem mass spectrometry (MS/MS) and further supported by 1H NMR spectroscopy. Alternating alkyne and activated ester moieties of copolymer 3 were further functionalized with organic azides and amines using sequential Cu-catalyzed azide–alkyne click (CuAAC) and amidation reactions, providing dually functionalized poly(acrylamide-alt-triazole) polymers 5. Water-soluble alternating poly(acrylic acid-alt-triazole) copolymers 9 were obtained by saponification of HFIP esters. 1H and 19F NMR spectroscopy, IR spectroscopy as well as gel permeation chromatography (GPC) were used to characterize the polymers before and after functionalization.