Amphiphilic Water Restructuring and Cooperativity

在这个由化学部门化学结构动力学和机理（CSDM-A）项目资助的项目中，普渡大学的Dor Ben-Amotz教授和他的研究小组正在研究水和亲水和亲油分子之间的相互作用。这些分子在生物过程的自组装和协调以及环境和地质化学中起着至关重要的作用。这项研究解决了关于小分子（如醇）对水的重组及其在更复杂结构（如生物膜）的自组装中的作用的开放性问题。这些问题是用实验和理论方法相结合的定量解决。这些结果被用来量化水介导的驱动力，这种驱动力导致了生物和地球化学系统中形成的结构的自组装。采用拉曼多元曲线分辨率，获得了两亲性溶质扰动下水分子的水合壳振动谱。采用高精度密度和声速实验测量了这类溶质的偏摩尔体积和可压缩性。在经典计算和量子计算的帮助下，获得了不能仅从实验中明确确定的额外分子/机制信息。由二元和高阶聚集体形成（自组装）引起的水结构变化是通过水合壳光谱、偏摩尔体积和可压缩性的浓度依赖性来量化的。溶质大小依赖的水重组，以及相关的交叉现象，使用温度和压力依赖的研究，延伸到水的正常冰点和沸点之外。理论计算阐明了水结构变化与实验测量的水化壳谱、偏摩尔体积和可压缩性之间的联系。结果用于量化溶质-溶质、溶质-水和水-水对平均力聚集势的贡献，以及相关的能量和熵变化。这项工作的更广泛影响包括开发用于定量液态分子相互作用的实验方法和理论建模策略，以及研究生和本科生的培训，以及将写作纳入本科STEM课程。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In this project funded by the Chemical Structure Dynamics and Mechanism (CSDM-A) program of the Chemistry Division, Professor Dor Ben-Amotz and his research group at Purdue University are investigating the interactions between water and molecules that are both water-loving and oil-loving. Such molecules play a vital role in the self-assembly and orchestration of biological processes, as well as in environmental and geological chemistry. This research addresses open questions concerning the restructuring of water by small molecules such as alcohols and its role in the self-assembly of more complex structures such biological membranes. These questions are quantitatively addressed using a combination of experimental and theoretical methods. The results are used to quantify the water-mediated driving forces that lead to the self-assembly of structures such as those formed in biological and geochemical systems. Raman multivariate curve resolution is used to obtain hydration-shell vibrational spectra of water molecules that are perturbed by amphiphilic solutes. High precision density and sound velocity experiments are used to measure the partial molar volumes and compressibilities of such solutes. Additional molecular/mechanistic information that cannot be unambiguously determined from experiments alone is obtained with the aid of classical and quantum calculations. Water structure changes induced by the formation (self-assembly) of binary and higher-order aggregates are quantified using the concentration dependence of hydration-shell spectra, partial molar volumes, and compressibilities. Solute size dependent water restructuring, and related crossover phenomena, are investigated using temperature and pressure dependent studies extending beyond the normal freezing and boiling points of water. Theoretical calculations are used to elucidate the connection between water structure changes and experimentally measured hydration-shell spectra, partial molar volumes and compressibilities. The results are used to quantify solute-solute, solute-water, and water-water contributions to aggregation potentials of mean force, as well as the associated energy and entropy changes. Broader impacts of this work include the development of experimental methods and theoretical modeling strategies for quantifying molecular interactions in the liquid state, as well as the training of graduate and undergraduate students, and the integration of writing into undergraduate STEM courses.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.