The facile and efficient functionalization of porous poly(glycidyl methacrylate) (pGMA) microspheres via hetero Diels–Alder (HDA) chemistry with poly(3-O-acryloyl-1,2:5,6-di-O-isopropylidene-α-D-glucofuranoside) (pAIpGlc) prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization employing electron deficient thiocarbonylthio compounds (benzyl pyridin-2-yldithioformate (BPDF)) is described in detail. The efficiency of the employed ‘grafting to’ approach is qualitatively and quantitatively analyzed. Initially the microspheres are functionalized with a highly reactive diene – cyclopentadiene (Cp) – in one step with sodium cyclopentadienide, and subsequently reacted with a protected glycopolymer (number-average molecular weight, Mn = 4200 g mol−1; polydispersity index, PDI = 1.2) that carries a thiocarbonyl moiety functioning as a dienophile. The functionalization of the microspheres is achieved under mild conditions (T = 50 °C) with trifluoroacetic acid (TFA) as a readily removable catalyst. Deprotection of the grafted pAIpGlc to poly(3-O-acryloyl-α,β-D-glucopyranoside) (pAGlc) can be performed after functionalization in one pot with formic acid at ambient temperature. The obtained loading capacity is 2.63 × 1019 chains per g and the grafting density is close to 0.16 chains per nm2. Quantitative analysis of the grafting densities is achieved via elemental analysis; the pore size distribution before functionalization was analyzed by inverse size exclusion chromatography (iSEC). Further employed characterization techniques include scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and high resolution attenuated total reflectance (ATR) FT-IR microscopy supporting the successful modification of the microspheres.
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