Living anionic polymerization of the amphiphilic monomer 2-(4-vinylphenyl)pyridine

The amphiphilic monomer 2-(4-vinylphenyl)pyridine(VPPy) has been successfully polymerized using a complex of sec-butyllithium (s-BuLi) with lithium chloride (LiCl) and coordination of VPPy with LiCl at -45 degrees C for 72 h without side reactions such as cross-linking and branching. However, it takes 3 days to complete the polymerization with 100% yield, and the polydispersity index (M-w/M-n = 1.15) was relatively broad. In contrast, the anionic polymerization using diphenylmethyl potassium (DPM-K) as the weak initiator was more feasible. The yield of the polymer reached 100% within 150 min at -78 degrees C, which significantly reduced polymerization time with a narrow molecular weight distribution below 1.1. To investigate their living nature and reactivity, the block copolymerization of VPPy with styrene, isoprene, 2-vinylpyridine, and methyl methacrylate were carried out by sequential anionic polymerizations without additives such as LiCl and Et2Zn. The resulting block copolymers of PVPPy-b-PMMA in tetrahydrofuran showed the microphase separation, which was confirmed by transmission electron microscopy.