Synthesis and characterization of amphiphilic diblock copolymers of 2-(1-imidazolyl)ethyl methacrylate and styrene
AuthorRikkou-Kalourkoti, Maria D.
Panteli, Panayiota A.
Patrickios, Costas S.
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Six amphiphilic diblock copolymers based on the hydrophilic monomer 2-(1-imidazolyl)ethyl methacrylate (ImEMA) and the hydrophobic monomer styrene (Sty) were prepared by sequential reversible addition-fragmentation chain transfer (RAFT) polymerization. RAFT polymerization was performed via the use of 4-cyano-4-(dodecylsulfanylthiocarbonylsulfanyl)pentanoic acid (CDP) as the chain transfer agent and glacial acetic acid as the solvent. Amphiphilic diblock copolymers with a range of compositions were prepared, with ImEMA first blocks of constant (nominal) degree of polymerization (DP) equal to 100, and Sty second blocks of a DP between 18 and 482, having ImEMA contents between 15 and 80 mol%, as measured by 1H NMR spectroscopy in CDCl3. Only the Sty-rich (≥51 mol%) diblock copolymers were fully soluble in the solvent for gel permeation chromatography (GPC), tetrahydrofuranGPC analysis of these copolymers indicated molecular weights in the range of 15 to 34 kDa, and molecular weight dispersities ranging from 1.1 to 1.6. At room temperature, the side-group of the ImEMA units was stable in an acidic environment but hydrolyzed slowly under alkaline conditions. In bulk neutral samples, the ImEMA side-group was thermally stable up to ∼250 °C. Finally, dynamic light scattering and polarized light microscopy indicated that the Sty-rich diblock copolymers formed spherical micelles in chloroform, whereas all diblock copolymers formed anisotropic nanophases in water. © 2014 the Partner Organisations.