氢键是一种非共价键的分子间相互作用,在超分子构建和功能材料合成领域已经得到广泛运用。氢键作用也被应用于可控自由基聚合体系中,以实现对分子量、立构规整性以及序列分布的微结构精密调控。近年来的研究结果表明,氢键诱导作用可提高聚合物分子量控制及聚合物的间同立构规整度;并且,当使用氟醇作为氢键供体溶剂,分别以甲基丙烯酸甲酯(MMA),4-乙烯基毗啶(4VP)和2-乙烯基吡啶(2VP)为单体进行的可控自由基聚合,氢键作用改变了共聚单体的序列分布,证明了氢键诱导下的单体双键活化作用。这为利用分子间非共价键诱导构建聚合物微结构的精密合成提供了新的策略。
Hydrogen bond between molecules is a very important weak interaction. Hydrogen bonding has been applied to the controlled radical polymerization (CRP) system to achieve the dual control o1 molecular weight and stereoregularity, which makes the precision syntheses of polymers possible. However, the exact reason for the molecular weight control has not yet been realized. In the recent years, our group has focused on the hydrogen bonding induced controlled radical polymerization of methyl methacrylate, 4-vinybpyridine and 2-vinyl-pyridine. Control over molecular weight, tacticity and monomer sequence have been realized. Importantly, for the first time, the systematic research revealed that the hydrogen bonding can activate the monomer by electron induction interaction. The concept of hydrogen bonding promoting CRP or monomer-activating effect undoubtedly opened a new avenue to improve the controllability of those less active monomers.