Synthesis, Structure and Dynamics of Block Copolymer Based Organic Inorganic Hybrid Materials

嵌段共聚物基有机无机杂化材料的合成、结构与动力学

• 批准号: 0072009
• 负责人: Ulrich Wiesner
• 金额: $ 28.5万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2003-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0072009&HistoricalAwards=false
• 关键词: Synthesis; Structure; Dynamics; Block; Copolymer

In this research the synthesis, structure, structur-formation and dynamic mechanical behavior of block-copolymer-based, nano-structured organic-inorganic hybrid materials from organically modified ceramic (ORMOCER) precursors will be studied. To this end first a whole range of poly(isoprene-block ethyleneoxide) (PI-b-PEO) diblock copolymers with varying PEO volume fraction and narrow molecular weight distribution will be synthesized by anionic polymerization. These will be used as structure directing agents in the sol-gel process of a mixture of two metal alkoxides, added to the block copolymers in different amounts. In this way the full phase space for the mixture of PI-b-PEO diblock copolymers of various compositions with the inorganic materials will be explored. Special emphasis will be put on the synthesis of organic-inorganic hybrid materials with the bicontinuous gyroid morphology, a particularly interesting structure in block copolymers. The resulting structures will be analysed by small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) measurements. Results of this part will lead to a phase diagram comparable to that of diblock copolymer/homopolymer mixtures. Analysis of details of the phase diagram will be facilitated by the possibility to look at frozen-in, local transition domains in biphasic regions of the phase diagram simply by dissolution of block copolymer rich bulk samples. Furthermore, the large variability in the polymer as well as the sol-gel chemistry will be explored to synthesize hybrid materials with unknown property profiles. For particular compositions of the mixtures of organic and inorganic precursors the structure formation process during evaporation of the solvent under heating will be investigated using in-situ SAXS. By correlating these results with solid-state NMR measurements on silicon and aluminum, insights into the interplay between sol-gel chemistry and phase separation as well as into the pathways towards the final morphologies will be obtained. Finally, the present study will allow for a systematic investigation of the dynamic mechanical behavior of the resulting organic-inorganic hybrid materials. These materials can be looked at as model systems for the understanding of the mechanical behavior of commercially important polymer-clay nanocomposites. It is expected that this program will lead to advances in the fundamental understanding of the mechanisms of formation and behavior of structured block copolymer-silica hybrid materials. At the same time it will provide student training and learning at the interface between polymer science and inorganic chemistry.

本研究将研究以有机改性陶瓷（ORMOCER）为前驱体的嵌段共聚物基纳米结构有机-无机杂化材料的合成、结构、结构形成和动态力学行为。为此，首先将通过阴离子聚合合成具有不同PEO体积分数和窄分子量分布的聚（异戊二烯-嵌段环氧乙烷）（PI-b-PEO）二嵌段共聚物的整个范围。这些将在以不同量添加到嵌段共聚物中的两种金属醇盐的混合物的溶胶-凝胶过程中用作结构导向剂。以这种方式，将探索各种组成的PI-b-PEO二嵌段共聚物与无机材料的混合物的全相空间。特别的重点将放在有机-无机杂化材料的合成与双连续螺旋形态，一个特别有趣的结构在嵌段共聚物。将通过小角X射线散射（SAXS）和透射电子显微镜（TEM）测量分析所得结构。本部分的结果将得出与二嵌段共聚物/均聚物混合物相当的相图。通过简单地溶解富含嵌段共聚物的本体样品来观察相图的两相区域中的冻结的局部过渡域的可能性将促进相图的细节的分析。此外，在聚合物以及溶胶-凝胶化学的大的可变性将被探索合成杂化材料与未知的属性配置文件。对于有机和无机前体的混合物的特定组合物的结构形成过程中，在加热下的溶剂蒸发将使用原位SAXS研究。通过将这些结果与硅和铝的固态NMR测量相关联，将获得溶胶-凝胶化学和相分离之间的相互作用以及最终形态的途径。最后，本研究将允许系统的动态力学行为的有机-无机杂化材料的调查。这些材料可以被看作是模型系统的理解商业上重要的聚合物-粘土纳米复合材料的力学行为。预计该计划将导致结构化嵌段共聚物-二氧化硅杂化材料的形成和行为机制的基本理解的进展。同时，它将为学生提供高分子科学和无机化学之间的界面培训和学习。