Doubly Thermosensitive Block and Star Copolymers from Living Radical Polymerizations: Synthesis, Phase Transitions, and Applications

活性自由基聚合的双热敏嵌段和星形共聚物：合成、相变和应用

• 批准号: 0605663
• 负责人: Bin Zhao
• 金额: --
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0605663&HistoricalAwards=false
• 关键词: Doubly; Thermosensitive; Block; Star; Copolymers

TECHNICAL SUMMARY:This project seeks to develop well-defined thermosensitive block and star copolymers that exhibit double thermo-induced phase transitions in water, to achieve fundamental understanding of the effects of molecular weight and molecular structure on the phase behavior, and to elucidate the structures of temperature-induced self-assemblies in water. Specifically, a variety of linear and star block copolymers with controlled molecular weights, narrow molecular weight distributions, and well-defined architectures will be synthesized by living radical polymerization techniques. The functional monomers recently developed in the PIs laboratory will be used to construct these copolymers along with monomers whose corresponding homopolymers have been reported to exhibit thermoresponsive properties. The phase transitions of these polymers in water will be investigated by turbidimetry, variable temperature 1H NMR spectroscopy, fluorescence spectroscopy, dynamic and static light scattering, differential scanning calorimetry, and rheology measurement. Whether and how the molecular weight and molecular structure affect the responsive properties of block copolymers will be systematically studied. The nanostructures formed from self-assembly of these copolymers in water will be elucidated by transmission electron microscopy. The knowledge gained from this research will provide a guideline for designing thermosensitive water-soluble polymers with multiple transitions. The applications of doubly thermosensitive copolymers in catalysis and triggered release of substances will be pursued. NON-TECHNICAL SUMMARY:With the rapid advance of nanotechnology and biotechnology, intelligent materials that can respond to external stimuli are much needed. The double-thermosensitive water-soluble polymers from this research have potential for practical applications in drug delivery, chemical sensors, catalysis, and bio-nanotechnology. Moreover, this research project provides an excellent setting for training of students in polymer synthesis, characterization, design and fabrication of stimuli-responsive materials. Students at all levels will be integrated into the PIs research and education activities. The PI will also work with local high school teachers through summer programs in his laboratory to develop hands-on experiments for high school chemistry classes.

技术摘要：该项目旨在开发明确的热敏嵌段和星形共聚物，这些共聚物在水中表现出双重热诱导相变，以基本了解分子量和分子结构对相行为的影响，并阐明其结构水中温度诱导的自组装。具体来说，将通过活性自由基聚合技术合成具有受控分子量、窄分子量分布和明确结构的各种线性和星形嵌段共聚物。 PI实验室最近开发的功能单体将用于构建这些共聚物，以及据报道其相应均聚物表现出热响应特性的单体。这些聚合物在水中的相变将通过比浊法、变温 1H NMR 光谱、荧光光谱、动态和静态光散射、差示扫描量热法和流变测量来研究。将系统地研究分子量和分子结构是否以及如何影响嵌段共聚物的响应性能。这些共聚物在水中自组装形成的纳米结构将通过透射电子显微镜来阐明。从这项研究中获得的知识将为设计具有多重转变的热敏水溶性聚合物提供指导。将研究双热敏共聚物在催化和物质触发释放方面的应用。非技术概要：随着纳米技术和生物技术的快速发展，非常需要能够响应外部刺激的智能材料。这项研究的双热敏水溶性聚合物在药物输送、化学传感器、催化和生物纳米技术方面具有实际应用潜力。此外，该研究项目为学生在刺激响应材料的聚合物合成、表征、设计和制造方面的培训提供了良好的环境。各级学生都将参与 PI 的研究和教育活动。 PI 还将通过实验室的暑期项目与当地高中教师合作，为高中化学课程开发实践实验。