Collaborative Research: Fundamentals of Block Copolymer Ordering During Cold Zone Annealing

技术概述：通过热区退火对嵌段共聚物（BCP）薄膜进行非平衡加工，有望克服传统热力学方法的重大挑战，为高科技应用创造无缺陷和远程有序的功能薄膜。热区退火包括使移动的热温度梯度穿过薄膜的平面以局部熔化和固化薄膜。最近，低温“冷区退火”或CZA版本被证明具有令人鼓舞的结果。由于大多数嵌段共聚物在熔点以上的高温下会降解，因此CZA广泛适用于许多嵌段共聚物体系。结果表明，CZA在玻璃圆柱体上形成PS-PMMA嵌段共聚物薄膜的顺序动力学和取向提高了一个数量级。基于这些有希望的结果，CZA驱动的bcp有序现象的关键分子机制将在基础水平上进行研究。本研究将使用不同的嵌段共聚物体系来研究CZA的这些基本方面，以阐明CZA诱导嵌段共聚物薄膜体系有序的一般控制原理。该研究计划的一个重要组成部分依赖于对嵌段共聚物在CZA中的有序度进行活化能（Ea）分析，从粒径增长或相关长度发展来看，这是CZA速度(V)、最高温度（Tmax）、梯度量级(G)和BCP分子量（Mw）以及嵌段相互作用参数的函数。此外，定向排列的起源和机制将阐明使用图案和非图案的底物。非技术总结：嵌段共聚物材料在过去十年中一直是人们关注的焦点，因为它有可能解决从功能光子材料到太比特密度数据存储设备等广泛的新兴纳米技术需求。然而，使用这些材料的主要限制是存在缺陷。本提案将寻求理解一个新的退火平台的基本原理，该平台显著降低了缺陷去除的障碍。这些基本原理可能导致新的加工技术，使许多工业相关领域取得进展。PI的学生将在阿贡国家实验室的先进光子源获得经验，允许在国家研究机构进行暴露和培训。该研究的一个积极组成部分旨在通过阿克伦早期大学高中项目和高等教育远程学习机会（PSEOP），以及通过阿克伦圣文森特圣玛丽高中和高分子科学与工程学院之间的一个新项目，让学生和教师都参与进来，让邻近高中的学生参与进来。此外，这项研究将涉及少数民族和妇女参与他们的研究项目，阿克伦大学和阿肯色大学小石城分校都以其研究项目中少数民族和妇女的高比例而闻名。此外，UALR的这个研究项目将在夏季通过一个名为“努力”的项目将中学科学教师纳入其中。让教师接触到包括合成和纳米表征在内的这项研究将提高他们的科学技能以及他们对该领域的理解，使他们成为更好的教育者。

TECHNICAL SUMMARY: Non-equilibrium processing of block copolymer (BCP) thin films via thermal zone-annealing promises to overcome significant challenges of traditional thermodynamic approaches to create defect free and long-range ordered functional films for high-tech applications. Thermal zone annealing involves passing a moving thermal temperature gradient across the plane of the film to locally melt and solidify the film. Recently a low temperature "cold zone annealing" or CZA version was demonstrated with promising results. Since most block copolymers will degrade at significantly high temperatures above melt point, CZA is broadly applicable to many block copolymer systems. Results for CZA on glassy cylinder forming PS-PMMA block copolymer films indicate up to an order of magnitude in enhanced ordering kinetics and alignment. Based on these promising results, key molecular mechanisms underlying the CZA driven ordering phenomena for BCPs will be examined at a fundamental level. This research will investigate these fundamental aspects of CZA using different block copolymers systems to illuminate general governing principles of CZA induced ordering of block copolymer thin film systems. An important component of the research plan relies on an Activation Energy (Ea) analysis of ordering of block copolymer in CZA from grain size growth or correlation length development as a function of CZA parameters of velocity (V), maximum temperature (Tmax), and gradient magnitude (G) and the BCP molecular weight (Mw) and block-block interaction parameter. In addition, the origin and mechanism of orientational alignment will be elucidated using both patterned and non-patterned substrates.NON-TECHNICAL SUMMARY:Block copolymer materials have been the focus over the last decade as potential solutions to a wide range of emerging nanotechnology needs from functional photonic materials to terabit density data storage devices. The major limitation to the use of these materials, however, is the presence of defects. This proposal will seek to understand the fundamentals of a new annealing platform that significantly reduces the barrier to defect removal. These fundamentals could lead to new processing techniques allowing advances in many industrially relevant fields. The PI's students will get experience at the Advanced Photon Source at Argonne National Lab allowing for exposure and training at national research facilities. An active component of the research is aimed at involving students at adjacent high-schools through the Akron Early College High School program as well the Post Secondary Distance Learning Opportunities (PSEOP) and through a new program between St. Vincent St. Mary's High School in Akron and the College of Polymer Science and Engineering involving both students and teachers. In addition, the research will involve minority and women participation in their research program and both the University of Akron and University of Arkansas at Little Rock are both well known for their high ratio of minorities and women in research programs. In addition, this research project at UALR would incorporate secondary high school science teachers during the summer through a program known as STRIVE. The exposure of the teachers to this research including synthesis and nanocharacterization would improve their science skills as well as their understanding of the field making them better educators.