CAREER: Polymer Absorption and Transport in Nanopores

职业：纳米孔中的聚合物吸收和运输

• 批准号: 0449736
• 负责人: Chang Ryu
• 金额: $ 44.5万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0449736&HistoricalAwards=false
• 关键词: CAREER; Polymer; Absorption; Transport; Nanopores

The goal of this CAREER proposal is to understand and control polymer adsorption and transport in nanopores at a molecular level and to elucidate how these processes differ from those on flat surfaces. These studies are particularly relevant to applications involving polymer separation in high performance liquid chromatography (HPLC), nanoporous support design in polyolefin and hydrogenation catalysis, and manipulation of macromolecules in nanofluidic channels. This proposal aims to bridge the existing knowledge gap between polymer adsorption and separation in HPLC analysis. In particular, the critical role of transport limitations associated with the chain transfer from a bulk solution to the nanopore opening, and the subsequent transport and adsorption in nanopores remains poorly understood. To achieve a better understanding of these phenomena, polymer adsorption will be studied in nanoporous silica particles containing well-defined tortuous pores of high specific surface areas and the results will be compared with polymer transport inside well-controlled nanopore channel architectures present in anodized aluminum oxide (AAO) membranes. In addition, electron microscopy will be applied to directly study the morphology of polymers in such nanoporous substrates. Our preliminary results motivate us to focus the proposed research into four specific objectives: (1) Studying the role of nanopore size on the chromatographic [i.e., continuous] and batch conditions for polymer adsorption; (2) Examining "steric crowding" effects at the pore mouth for adsorption in nanoporous silica; (3) Understanding chain "frustration" effects of terminally-adsorbed polymers confined in nanopores using end-functional polymers and highly asymmetric block copolymers; and (4) Investigating polymer chain transport through AAO nanochannel membranes using TEM and membrane osmometry. The proposed research will enable investigation of surface-bound polymers in nanopores and will help to understand how polymer chains diffuse into the pores from the mouth, especially in pores that are small compared to the size of the chains. The proposed research will have a broad impact on the development of novel polymer HPLC techniques, which can complement existing size exclusion chromatography techniques. An educational website called "Virtual Polymer Laboratory" (VPL) will be developed to provide multimedia educational resources related to polymers and general chemistry. To impact education at all levels, the VPL website will be further improved by establishing partnerships with (a) the Troy Junior Museum; (b) local high schools and (c) undergraduate-only colleges using the following avenues: (i) Developing a "Hands-on Science Family Program on Macromolecules" for the Troy Junior Museum, particularly targeted towards K-6 kids and their parents (ii) Improving "Bringing Nanotechnology to the Classroom", an existing program in the NSF Nanoscale Science and Engineering Center at RPI (iii) Designing guest lectures on polymer HPLC, specifically for undergraduates. To attract students beyond my contact-based activities, the educational program will be further evolved into web-based educational materials containing multimedia clips of pre-recorded "virtual" program demonstrations. The research results will be employed to improve polymer education, by exposing both undergraduate and graduate students to cross-disciplinary research involving polymer adsorption, HPLC and microscopy.

该CAREER提案的目标是在分子水平上理解和控制纳米孔中的聚合物吸附和运输，并阐明这些过程与平坦表面上的过程有何不同。这些研究是特别相关的应用，涉及聚合物分离的高效液相色谱（HPLC），纳米多孔支持设计聚烯烃和加氢催化，和操纵的大分子在纳米流体通道。该提案旨在弥合HPLC分析中聚合物吸附和分离之间的现有知识差距。特别是，与从本体溶液到纳米孔开口的链转移以及随后在纳米孔中的运输和吸附相关的运输限制的关键作用仍然知之甚少。为了更好地理解这些现象，聚合物吸附将在纳米多孔二氧化硅颗粒中进行研究，该颗粒含有高比表面积的明确的曲折孔，并且将结果与阳极氧化铝（AAO）膜中存在的良好控制的纳米孔通道结构内的聚合物传输进行比较。此外，电子显微镜将被应用于直接研究在这样的纳米多孔基板的聚合物的形态。我们的初步结果促使我们将拟议的研究集中在四个具体目标上：（1）研究纳米孔径对色谱的作用[即，连续]和间歇条件下进行聚合物吸附;（2）检查在纳米多孔二氧化硅中吸附的孔口处的“空间拥挤”效应;（3）使用末端官能聚合物和高度不对称嵌段共聚物理解限制在纳米孔中的末端吸附聚合物的链“阻挫”效应;和（4）使用TEM和膜渗透压测定法研究聚合物链通过AAO纳米通道膜的传输。拟议的研究将能够调查纳米孔中的表面结合聚合物，并将有助于了解聚合物链如何从口腔扩散到孔中，特别是在与链的大小相比较小的孔中。 拟议的研究将对新型聚合物HPLC技术的发展产生广泛的影响，该技术可以补充现有的尺寸排阻色谱技术。将开发一个名为“虚拟聚合物实验室”（VPL）的教育网站，提供与聚合物和普通化学有关的多媒体教育资源。为了影响各级教育，VPL网站将通过以下途径与（a）特洛伊少年博物馆;（B）当地高中和（c）本科院校建立伙伴关系，进一步改进：（i）为特洛伊少年博物馆制定“高分子科学家庭实践方案”，特别是针对K-6儿童及其父母（ii）改进“将纳米技术带到课堂”，这是RPI NSF纳米科学与工程中心的现有计划（iii）设计关于聚合物HPLC的客座讲座，专门针对本科生。 为了吸引学生超越我的接触为基础的活动，教育计划将进一步演变成基于网络的教育材料，包含预先录制的“虚拟”程序演示的多媒体剪辑。 研究结果将被用来改善聚合物教育，通过暴露本科生和研究生的跨学科研究，涉及聚合物吸附，HPLC和显微镜。