非极性有机溶剂对分子内氢键弱化程度的单分子力谱定量研究

利用单分子力谱技术, 以3种不同醇解度的聚乙烯醇(PVA)为模型体系, 定量研究了非极性有机溶剂对分子内氢键强度的影响. 3种PVA样品在非极性有机溶剂中的分子内氢键强度均约为其在真空中强度的48%. 结果表明， 非极性有机溶剂对分子内氢键的弱化作用十分显著, 可削弱其约50%的本征氢键强度. 本文研究结果提示人们需重新审视液相环境对高分子单链弹性和非共价相互作用的影响.

Quantifying the Degree of Weakening Effect of Nonpolar Organic Solvent on the Strength of Intramolecular Hydrogen Bonding by Single-molecule Force Spectroscopy

The influence degree of nonpolar organic solvents on the strength of intramolecular hydrogen bonding （H-bond） have been quantitatively studied by taking three kinds of polyvinyl alcohol（PVA） with different alcoholysis degrees as the model system in this paper. The single-molecule force spectroscopy（SMFS） results show that the strengths of intramolecular H-bonds in three kinds of PVA in nonpolar organic solvents are ca.48% of those in vacuum. These findings indicate that the nonpolar organic solvent has a significant weakening effect on the intramole-cular H-bond， which can weaken its strength by ca.50%. This study suggests that the influence of liquid environments on the strengths of non-covalent interactions and the single-chain elasticities of polymers should be reconsi-dered.