Ballal Deepti, Chapman Walter G
Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, MS-362, Houston, Texas 77005, United States.
J Phys Chem B. 2015 Jun 4;119(22):6792-802. doi: 10.1021/acs.jpcb.5b00766. Epub 2015 May 22.
Fluid properties and phase behavior of systems such as glycol ethers, carboxylic acids, and proteins are affected by the competition between intra- and intermolecular hydrogen bonding. Here we study this competition by extending Wertheim's first-order thermodynamic perturbation theory to include intramolecular hydrogen bonding in chain molecules in the presence of an explicit water-like solvent. The theory derived here is found to be in good agreement with molecular simulation. It is shown that intramolecular association is most important for shorter chains at low temperature, low density, and high chain concentration. The theory is also extended into a density functional theory formalism to study the effect of intramolecular association on the structuring of the different segments of the molecules close to a hydrophobic surface. Intramolecular association is found to be enhanced close to the surface, with the total density of the system having the most effect on structuring close to the surface.
二醇醚、羧酸和蛋白质等体系的流体性质和相行为受到分子内和分子间氢键竞争的影响。在此，我们通过扩展韦特海姆一阶热力学微扰理论来研究这种竞争，该理论将分子内氢键纳入链状分子中，并存在类似水的明确溶剂。结果发现，这里推导的理论与分子模拟结果吻合良好。研究表明，在低温、低密度和高链浓度条件下，分子内缔合对于较短的链最为重要。该理论还扩展为密度泛函理论形式，以研究分子内缔合对靠近疏水表面的分子不同片段结构的影响。研究发现，靠近表面时分子内缔合增强，体系的总密度对靠近表面的结构影响最大。
