Translocation and phase separation kinetics in polyelectrolyte solutions

聚电解质溶液中的易位和相分离动力学

• 批准号: 1104362
• 负责人: Murugappan Muthukumar
• 金额: $ 39万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1104362&HistoricalAwards=false
• 关键词: Translocation; phase; separation; kinetics; polyelectrolyte

TECHNICAL SUMMARY:The movement of charged macromolecules in crowded aqueous solutions and the thermodynamic stability of such multi-component macromolecular systems are of central importance in various forms of life. The thermodynamic and dynamic behaviors of polyelectrolyte solutions in water exhibit extremely complex phenomenology and pose many challenges for a fundamental understanding. The proposal is to perform electrophysiology and light scattering experiments pertinent to a fundamental understanding of (a) translocation of single polyelectrolyte molecules through protein and solid-state nanopores, (b) kinetics of phase separation in polyelectrolyte solutions, and (c) dynamics of elastic modes accompanying phase transitions in polyelectrolyte gels. Specifically, the proposed research addresses (a) the dynamics of polyelectrolyte chains with specified architecture (uniformly charged linear molecules, diblock copolymers of charged and uncharged polymers, branched polyelectrolytes, and polyelectrolyte complexes) through nanopores (hemolysin protein pore with fixed pore diameter and silicon nitride pores with controllable variations in diameter), (b) phase separation kinetics of sodium poly(styrene sulfonate) in water containing known amounts of barium chloride, and (c) dynamical fluctuations of polyacrylamide-polyacrylic acid copolymer gels accompanying their first order volume phase transitions. The proposed research will establish the validity and generality of a few newly discovered phenomena related to translocation of synthetic polyelectrolyte molecules through protein pores, phase separation mechanism in electrically charged polymeric solutions, and pretransitional slowing down of elastic modes in gels.NON-TECHNICAL SUMMARY:The proposed research will have impact in separation science, characterization methods for charged macromolecules in aqueous media, and medical research, and a number of key industries including food, cosmetics, personal care products, pharmaceuticals, and the human genome sequencing project. Polyelectrolytes are among the most important but least understood materials. This research will use a number of experimental methods together with theory and simulations in an attempt to understand how polyelectrolyte molecules are able to pass through pores in protein assemblies and other biological systems. Training of graduate students in this highly interdisciplinary research area is the primary educational component of the proposed activity.

技术概述：带电大分子在拥挤的水溶液中的运动和这种多组分大分子体系的热力学稳定性在各种形式的生命中都是至关重要的。聚电解质溶液在水中的热力学和动力学行为表现出极其复杂的现象学，并对基本理解提出了许多挑战。建议进行电生理学和光散射实验，以从根本上了解(A)单个聚电解质分子通过蛋白质和固态纳米孔的移位，(B)聚电解质溶液中相分离的动力学，以及(C)聚电解质凝胶中伴随相变的弹性模式的动力学。具体地说，拟议的研究涉及(A)具有特定结构的聚电解质链(均匀带电的线性分子、带电和不带电的聚合物的两嵌段共聚物、支化聚电解质和聚电解质复合体)通过纳米孔(具有固定孔径的溶血素蛋白孔和直径可控的氮化硅孔)的动力学，(B)聚苯乙烯磺酸钠在含有已知数量的氯化钡的水中的相分离动力学，以及(C)聚丙烯酰胺-聚丙烯酸共聚凝胶的动态波动以及它们的一级体积相变。这项拟议的研究将确定一些新发现的现象的有效性和普遍性，这些现象与合成聚电解质分子通过蛋白质孔的移位、带电聚合物溶液中的相分离机制以及凝胶中弹性模式的过渡期前减速有关。非技术摘要：拟议的研究将对分离科学、水介质中带电大分子的表征方法、医学研究以及食品、化妆品、个人护理产品、制药和人类基因组测序计划等一些关键行业产生影响。聚电解质是最重要但最不为人所知的材料之一。这项研究将使用一些实验方法，结合理论和模拟，试图了解聚电解质分子如何能够通过蛋白质组件和其他生物系统中的孔。在这一高度跨学科的研究领域对研究生进行培训是拟议活动的主要教育组成部分。