Polymer Solutions, Coil-Globule and Other Phase Transitions, US-Turkey Cooperative Research

描述：该项目支持麻省大学聚合物科学与工程教授Frank Karasz博士和两位土耳其科学家的合作：土耳其Gebze马尔马拉研究中心（MRC）基础科学研究所主任Bahattin Baysal博士和伊斯坦布尔Bogazici大学研究助理，也是MRC聚合物研究项目的研究专家E. Elif Hamurcu博士。该研究涉及聚合物链在稀溶液中的转变，从一个膨胀的线圈在良好的溶剂到一个崩溃的，紧凑的球形结构在不良的溶剂。目前还没有通过实验或理论手段对链崩溃进行全面和定量的认识。这种现象与某些生物过程密切相关，包括DNA折叠和蛋白质变性以及三级结构的形成。在这个项目中，两位科学家将使用实验技术，包括动态光散射和粘度法，详细研究二元和三元体系中极性大分子在近θ条件下的线圈坍塌。网络系统中的体积相变也将被研究。项目范围：该项目汇集了两位在聚合物领域具有丰富研究经验和较强研究能力的科学家。Karasz博士用量热法和散射法研究了多肽的螺旋线圈转变，以及溶液中线性和星形、柔性和半柔性大分子的构象变化，这些构象变化是分子量、浓度、结构、离子强度和限制几何形状的函数。Baysal博士研究了稀溶液中的链特性，包括通过理论分析、粘度学和介电实验研究了线圈到球体的转变。这些互补的专业知识为他们的研究兴趣提供了一个合乎逻辑的组合。来自MRC的一名博士后也将参与马萨诸塞大学的研究。该项目符合国际项目部的目标。

Description: This project supports collaboration by Dr. Frank Karasz, Professor of Polymer Science and Engineering at the University of Massachusetts, and two Turkish scientists: Dr. Bahattin Baysal, Director, Research Institute of Basic Sciences at the Marmara Research Centre (MRC), Gebze, Turkey and Dr. E. Elif Hamurcu, a Reserach Assistant at Bogazici University in Istanbul and also a Research Specialist in the Polymer Research Project at the MRC. The research deals with the transition of a polymer chain in dilute solution from an expanded coil in a good solvent to a collapsed, compact globular structure in a poor solvent. A comprehensive and quantitative understanding of chain collapse has not yet been achieved through experimental or theoretical means. The phenomena is intimately related to certain biological processes, including DNA folding and protein denaturation and tertiary structure formation. In this project the two scientists will use experimental techniques, including dynamic light scattering and viscometry, in detailed studies of coil collapse in near theta conditions for polar macromolecules in binary and ternary systems. Volume-phase transitions in network systems will also be investigated. Scope: This project brings together two scientists with excellent experiences and strong capabilities in research in the field of polymers. Dr. Karasz has investigated the helix-coil transition of polypeptides with calorimetric and scattering methods, and the conformational variation of linear and star, flexible and semiflexible macromolecules in solution as functions of molecular weight, concentration, architecture, ionic strength and confining geometry. Dr. Baysal has studied chain characteristics in dilute solution including coil-to-globule transition with theoretical analysis and viscometric and dielectric experiments. These complementary expertise provide for a logical combination of their research interests. A postdoctorate from MRC also will participate in the research at the U. of Massachusetts. The project meets the objectives of the Division of International Programs.