RUI: Solvation in Bulk and Confined Polyethylene Glycol

水（H2O）溶解食盐和糖等物质，因为水分子与盐离子（钠阳离子（Na+）和氯阴离子（Cl-））或糖分子结合，因此打破了这些化合物的固体晶格。 其他液体（酒精、液氨和液态二氧化碳等）也可以溶解化学物质。 一种有趣的液体，其溶剂化性质尚未得到很好的研究是聚乙二醇（PEG）。 PEG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。 PEG是无毒的，并且已经成功地用作化学合成中的环境友好溶剂，但是我们仍然不太了解它们的溶剂化性质。在这个由化学结构、动力学和机制-化学系的一个项目支持的项目中，Markus Hoffmann教授，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产生关于PEG作为溶剂的新知识。 霍夫曼教授的研究计划利用核磁共振（NMR）光谱，一种与医学中使用的磁共振成像（MRI）工具相关的技术。 NMR光谱提供有关分子的结构和运动以及分子之间相互作用的信息。 霍夫曼实验室还采用计算机模拟液体系统。 高级核磁共振光谱学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，Brockport的学生不仅在该项目的具体主题方面，而且在国际研究合作方面都获得了宝贵的经验。该项目的目标是发展对聚乙二醇（PEG）溶剂化的理解。为了实现该项目的目标，正在测量PEG溶液的热物理性质密度、粘度和自扩散系数，以验证用于散装相同溶液的分子动力学（MD）模拟的力场。验证的力场，然后用于MD模拟的PEG溶液中的限制在介孔二氧化硅孔与表面改性和无溶剂化的限制效应的理解，并探讨孔表面改性的影响。 该研究小组将解释来自几种NMR光谱技术的实验数据，这些技术可以探测PEG在孔限制内的动力学和分子相互作用。NMR实验包括动态核极化（DNP）增强NMR光谱;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PEG和“PEG化”化合物广泛用于制药技术，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，改善研究和研究培训的基础设施在纽约州立大学布罗克波特，并为学生增加了一个有意义的国际研究经验。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.