RUI: Solvation in Bulk and Confined Polyethylene Glycol

水（H2O）可以溶解食盐和糖等物质，因为水分子与盐离子（钠离子（Na+）和氯离子（Cl-））或糖分子结合，从而破坏了这些化合物的固体晶格。其他液体（酒精、液态氨和液态二氧化碳等）也能溶解化学物质。聚乙二醇（PEG）是一种有趣的液体，其溶剂化性质尚未得到很好的研究。聚乙二醇不同于其他常见的液体，因为它是由碳、氢和氧原子组成的长链。聚乙二醇是无毒的，已成功地作为环境友好型溶剂用于化学合成，但我们对其溶剂化性质仍然知之甚少。在化学系化学结构、动力学和机理a项目的支持下，Markus Hoffmann教授和他在纽约州立大学布罗克波特学院的本科生以及德国的国际合作者正在研究聚乙二醇作为溶剂的新知识。Hoffmann教授的研究项目利用核磁共振（NMR）光谱学，这是一种与医学中使用的磁共振成像（MRI）工具相关的技术。核磁共振光谱学提供了分子结构和运动的信息，以及分子之间的相互作用。霍夫曼实验室也采用计算机模拟液体系统。先进的核磁共振光谱和计算研究正在与德国达姆施塔特大学的Gerd Buntkowsky教授和Michael Vogel教授合作进行。霍夫曼教授带领的纽约州立大学布罗克波特分校的学生在夏季访问达姆施塔特，并在那里进行研究。因此，布罗克波特的学生不仅在项目的具体主题方面获得了宝贵的经验，而且在国际研究合作方面也获得了宝贵的经验。该项目的目标是发展对聚乙二醇（PEG）溶剂化的理解。为了实现项目目标，研究人员测量了聚乙二醇溶液的热物理性质、密度、粘度和自扩散系数，以验证在分子动力学（MD）模拟中使用的力场。然后，将验证的力场用于在有和没有表面修饰的介孔二氧化硅孔中约束PEG溶液的MD模拟，以了解约束对溶剂化的影响，并探索孔表面修饰的影响。研究小组将解释来自几种核磁共振光谱技术的实验数据，这些技术可以探测PEG在孔隙限制内的动力学和分子相互作用。核磁共振实验包括动态核极化（DNP）增强核磁共振谱；我们感兴趣的溶质包括极化剂。这项研究的发现也有可能影响许多其他研究领域，因为聚乙二醇和“聚乙二醇化”化合物被广泛用于制药技术，以增加药物在循环系统中的寿命。该项目的其他更广泛的影响包括本科生的培训，改善纽约州立大学布鲁克波特分校的研究和研究培训基础设施，以及为学生增加有意义的国际研究经验。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。

Water (H2O) dissolves substances like table salt and sugar because the water molecules bind to the salt ions (sodium cations (Na+) and chloride anions (Cl-)) or sugar molecules and therefore break up the solid lattice of these compounds. Other liquids (alcohols, liquid ammonia and liquid carbon dioxide, and many others) can also dissolve chemical substances. An interesting liquid whose solvation properties have not been well-studied is polyethylene glycol (PEG). PEG is different from other common liquids because it is composed of long chains of carbon, hydrogen and oxygen atoms. PEGs are nontoxic and have been successfully used as environmentally benign solvents in chemical synthesis, but we still do not know very much about their solvation properties. In this project supported by the Chemical Structure, Dynamics and Mechanisms-A Program in the Division of Chemistry, Professor Markus Hoffmann, his undergraduate students at the State University of New York, College at Brockport, and international collaborators in Germany are generating new knowledge about PEG as a solvent. Professor Hoffmann’s research program utilizes nuclear magnetic resonance (NMR) spectroscopy, a technique related to the magnetic resonance imaging (MRI) tool used in medicine. NMR spectroscopy provides information about the structure and motions of molecules, as well as interactions between molecules. The Hoffmann laboratory also employs computer simulations of liquid systems. Advanced NMR spectroscopy and computational studies are being done in collaboration with Professors Gerd Buntkowsky and Michael Vogel at the University of Darmstadt in Germany. Professor Hoffmann’s SUNY-Brockport students visit Darmstadt and conduct research there during the summer. The Brockport students are therefore gaining valuable experience not only in the specific subject of the project, but also in international research collaboration.The goal of the project is to develop an understanding of solvation in polyethylene glycol (PEG). To achieve the project goal, the thermophysical properties density, viscosity and self-diffusion coefficient of PEG solutions are being measured to verify force fields used in molecular dynamics (MD) simulations of the same solutions in bulk. Verified force fields are then used for MD simulations of PEG solutions in confinement in mesoporous silica pores with and without surface modification to develop an understanding of confinement effects on solvation and to explore the influence of pore surface modification. The research team will interpret experimental data from several NMR spectroscopic techniques that probe dynamics and molecular interactions of PEG within the pore confinement. The NMR experiments include dynamic nuclear polarization (DNP) enhanced NMR spectroscopy; Solutes of interest include polarizing agents. The findings from the research have the potential to also impact many other research fields because PEGs and “PEGylated” compounds are widely used in pharmaceutical technologies to increase the lifetime of a drug in the circulatory system. Additional broader impacts of the project include the training of undergraduate students, improving the infrastructure of research and research training at SUNY Brockport, and the addition of a meaningful international research experience for the students.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.