Solvation Studies of Responsive Polymers in Solution and at Surfaces

ARRA声明：该奖项是根据2009年美国复苏和再投资法案(公法111-5)资助的。技术摘要：这项建议将研究聚合物微结构、溶剂添加剂和溶液成分对溶液和表面的低临界溶液温度(LCST)现象的影响。建议的研究将使用浊点行为的溶液状态光散射分析，主要使用体相显微分析自动数字熔点仪器来并行研究小尺度样品。其他分析技术也将被采用。例如，标记聚合物的荧光光谱将探测可见相分离开始和结束前后发生的聚合物聚集事件。小分子和大分子共溶质对具有结构同分异构体重复单元的各种聚合物的LCST的影响将被进行，以确定离子、共价和大分子共溶质对给定聚合物的LCST的影响。在这些溶液状态研究中产生的结构和化学信息将被用来开发新类型的刺激响应表面，这些表面在超疏水或亲水之间可逆地变化。还将研究此类表面的物理性能，以确定聚合物接枝的水化变化是否会改变表面的机械性能，如粘弹性和粘附性。这些表面需要用一系列的分析方法来研究。将跟踪与这些表面重组相关的表面结构变化，这些表面将以薄膜纳米复合材料的形式响应于主体水成分中的溶质，并且在适当的情况下，将被实时监测。非技术摘要：这项拟议的工作将研究刺激响应大分子溶解度的分子细节。这将主要涉及研究大分子的温度依赖的溶解度如何随着溶液中其他物种的存在而变化。这些研究将包括聚合物水溶液的研究和固体表面含聚合物涂层的研究。此类响应性聚合物的溶解度研究非常重要，因为此类材料是响应性催化剂和传感器的组成部分。聚合物的溶解度和聚合物溶解度的温度依赖性在决定蛋白质和酶的稳定性和活性方面也是至关重要的。将对大分子溶液行为的研究扩展到包括表面在内，将有助于更好地理解表面的响应润湿性和“智能”表面的设计。这种“智能”表面有可能成为自我清洁、附着力可控或表面摩擦力不同的新材料。这些研究将产生更广泛的影响，包括研究实验室和课堂上的本科生和研究生教育。在向工业界、主要是本科生为主的机构和国际场所的观众发表演讲时，向外部传播结果将宣传这些研究的结果。这项研究中使用的化学方法论将被开发成实验，用于大学一年级的化学课程，教育学生高分子水化过程中的焓和熵的后果。将促进国际研究合作，并将涉及与欧洲、中国和卡塔尔的团队的项目。

ARRA STATEMENT:This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).TECHNICAL SUMMARY: This proposal will examine the effect of polymer microstructure, solvent additives and solution components on lower critical solution temperature (LCST) phenomena both in solution and at surfaces. The studies proposed will use solution state light scattering analyses of cloud point behavior mostly using a bulk phase microanalytical automated digital melting point apparatus to study small scale samples in parallel. Other analytical techniques will be employed too. For example, fluorescence spectroscopy with labeled polymers will probe polymer aggregation events that occur before and after visible phase separation starts and ends. The effects of small molecule and macromolecular co-solutes on LCSTs of a variety of polymers with structurally isomeric repeating units will be carried out to determine how ionic, covalent and macromolecular co-solutes affect a given polymer's LCST. The structural and chemical information generated in these solution-state studies will then be used to develop new sorts of stimuli-responsive surfaces that reversibly change between being superhydrophobic or hydrophilic. Such surfaces physical properties will also be studied to determine if the hydration changes of the polymer grafts alter surface mechanical properties such as viscoelasticty and adhesion. These surfaces with be studied using a battery of analytical methods. The surface structural changes associated with reorganization of these surfaces that will be in the form of thin film nanocomposites in response to solutes in bulk water component will be followed, and, in suitable cases, will be monitored in real time.NON-TECHNICAL SUMMARY: This proposed work will study the molecular details of stimuli-responsive macromolecular solubility. This will primarily involve studies of how a macromolecule's temperature-dependent solubility changes in response to the presence of other species in solution. These studies will include studies of aqueous polymer solutions and studies of polymer-containing coatings on solid surfaces. Such responsive polymer solubility studies are important because such materials are components of responsive catalysts and sensors. Polymer solubility and the temperature dependence of polymer solubility is also critically important in determining the stability and activity of proteins and enzymes. Extending studies of solution behavior of macromolecules to include surfaces will lead to a better understanding of responsive wettability of surfaces and the design of 'smart' surfaces. Such 'smart' surfaces have potential as new materials that are self cleaning, that have controllable adhesion, or that have varied surface friction. These studies will have broader impacts that include both undergraduate and graduate education in the research laboratory and classroom. Extramural dissemination of results in presentations to audiences in industry, at predominantly undergraduate institutions, and at international venues will publicize the results of these studies. The chemical methodology used in this research will be developed into experiments that will be used in freshman chemistry courses to educate students about the consequences of enthalpy and entropy in macromolecule hydration. International research collaborations will be fostered and will involve programs with groups in Europe, China, and Qatar.