Lamellae Formation and Reorientation in Diblock Copolymers

二嵌段共聚物中片层的形成和重新取向

• 批准号: 0100903
• 负责人: Jorge Vinals
• 金额: $ 22.2万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0100903&HistoricalAwards=false
• 关键词: Lamellae; Formation; Reorientation; Diblock; Copolymers

0100903VinalsThis research project will use analytical and computational techniques to study the formation, stability and coarsening of lamellar phases in diblock copolymers. Although block copolymers are already widely used in industry, newer technologies that rely on high performance polymeric materials often require precise control of the polymer microstructure and its self-assembly. Processing by temperature quench or solvent casting from a high temperature isotropic phase always leads to the formation of a polycrystalline structure comprised of domains or grains of differently oriented lamellae. The focus of this research is on mechanisms controlling long-ranged orientational order, including the reorientation of lamellar phases by reciprocating shears, and the motion of topological defects and its effect on coarsening of the lamellar structure. A theoretical analysis is carried out at a mesoscopic level to find nonlinear solutions under imposed, reciprocating shears, as well as to elucidate their stability. Viscoelastic contrast between the microphases is explicitly taken into consideration. In addition, the longest relaxation times in the lamellar phase are likely to be determined by the spatial distribution and motion of topological defects. The motion of grain boundaries, disclinations (in two-dimensional samples), and dislocations is considered, as well as their effect on the coarsening times of the microstructure, and on the possible existence of asymptotic self-similarity.%%%This research project will use analytical and computational techniques to study the formation, stability and coarsening of lamellar phases in diblock copolymers. Although block copolymers are already widely used in industry, newer technologies that rely on high performance polymeric materials often require precise control of the polymer microstructure and its self-assembly. Processing by temperature quench or solvent casting from a high temperature isotropic phase always leads to the formation of a polycrystalline structure comprised of domains or grains of differently oriented lamellae.The focus of this research is on mechanisms controlling long-ranged orientational order and the motion of topological defects and its effect on coarsening of the lamellar structure.***

0100903Vinals本研究项目将使用分析和计算技术来研究二嵌段共聚物中层状相的形成、稳定性和粗化。 虽然嵌段共聚物已经广泛应用于工业中，但依赖于高性能聚合物材料的新技术通常需要精确控制聚合物微观结构及其自组装。 由高温各向同性相通过温度淬火或溶剂浇铸进行的加工总是导致形成由不同取向薄片的畴或晶粒组成的多晶结构。 本研究的重点是控制长程取向秩序的机制，包括往复剪切的层状相的重取向，和拓扑缺陷的运动及其对层状结构粗化的影响。 理论分析进行了在介观水平下施加，往复剪切，以及阐明其稳定性，找到非线性的解决方案。 微相之间的粘弹性对比明确考虑。 此外，最长的弛豫时间在层状相很可能是由拓扑缺陷的空间分布和运动。 考虑了晶界、向错（二维样品中）和位错的运动，以及它们对微观结构粗化时间的影响，以及对可能存在的渐近自相似性的影响。本研究计画将利用分析与计算技术来研究二嵌段共聚物中层状相的形成、稳定性与粗化。 虽然嵌段共聚物已经广泛应用于工业中，但依赖于高性能聚合物材料的新技术通常需要精确控制聚合物微观结构及其自组装。 从高温各向同性相通过温度淬火或溶剂浇铸的加工总是导致形成由不同取向的片晶的畴或晶粒组成的多晶结构。本研究的重点是控制长程取向有序和拓扑缺陷运动的机制及其对片晶结构粗化的影响。