Opportunities in Block Copolymers: Reactive Rod/Coils and Magnetooptic Nanocomposites

提出的研究将进一步提高嵌段共聚物进入更高价值的高科技应用的可能性，例如化学图案表面涂层，光刻掩模和改进的光学元件。为此，研究者提出了两个广泛相关的基础研究领域：(1)用表面反应性棒/线圈二嵌段共聚物创造纳米图案；(2)用纳米颗粒填充的嵌段共聚物制造可调谐磁光材料。在这两个项目中，PI之前在嵌段共聚物加工和结构-性能表征方面的经验将为构建主体共聚物与衬底和/或应用领域之间，或主体聚合物与表面工程纳米颗粒之间的结构和化学相互作用提供坚实的基础，从而确定最终的纳米复合材料形态，从而实现新的和增强的物理性能。对如何最好地创建基于嵌段共聚物的有序体系的原理的深入了解将对许多新兴技术具有广泛的适用性。关键是了解加工条件如何与化学结构相互作用，以达到理想的最终状态，从而提供基于bcp的优质材料。棒状/线圈状bcp及其与线圈状和棒状均聚物的共混物在很大程度上尚未被探索，并提供了一个了解液态结晶度在微相分离中的作用的机会。重点将放在棒/线圈-线圈混合物上，以研究棒BCP胶束，以及在棒块上存在的反应基团，以提供锁定形态的手段，用于调节衬底相互作用，并创建合成的各向异性有机纳米物体，然后可以用作分层自组装的独特构建块。利用超顺磁性纳米粒子在bcp中进行空间模板化制备具有磁场可调光学性能的聚合物-无机材料自组装纳米复合材料。表面工程纳米颗粒将被隔离在BCP中，由于它们的小尺寸（单畴颗粒），应该比相应的块状材料表现出更好的性能。通过选择具有足够分子量的BCP，使微畴的周期性提供可见波长光子禁隙（PBG），这些研究人员将制造出磁场可调谐的PBG材料。通过复合材料的场相关Verdet常数，这些材料具有偏振旋转器和光隔离器（“单向光阀”）的潜力。此外，纳米颗粒- bdp形态的实验数据集将用于与纳米颗粒- bcp自组装几何形状的最新理论模型进行比较。这个项目有几种影响社会的方式。研究生参观其他大学和行业的设想是给他们更广泛的经验，并获得新的仪器。PI有几个非常富有成效的合作：C. Ober和S. Gruner（康奈尔大学）-嵌段共聚物合成和同步加速器散射(3-4名学生常规访问CHESS和短期（一周）访问Ober实验室；S. Margel（以色列Var-Llan） -纳米粒子合成（由于以色列目前的情况，还没有学生参观他的实验室）和B. Lotz Strasbourg) - TEM和电子衍射表征（对CNRS进行为期一个月的访问）。PI最近与另一位教授和一名前研究生共同创办了一家初创公司（Omni Guide Communications, Inc.），为如何将大学的技术转移到市场提供了一个视角。在过去的12年中，PI共提交了15项专利公开，并颁发了5项专利。此外，PI的小组一直在麻省理工学院接待几名本科生，称为urop。他们成功地参与了研究，并共同发表了几篇论文。

The research proposed will further the possibility that block copolymers gain entry into higher value, high technology applications, such as chemically patterned surface coatings, lithographic masks and improved optical components. To this end, the investigator proposes two broadly related fundamental research areas: (1) creation of nanopatterns with surface-reactive rod/coil diblock copolymers and (2) fabrication of tunable magneto-optical materials from nanoparticle-filled block copolymers. In both these projects, the PI's previous experience with block copolymer processing and structure-property characterization will provide a firm base to build structure and chemical interactions between the host copolymer and a substrate and/or an applied field, or between the host polymer and surface engineered nanoparticles determines the resultant nanocomposite morphology will permit attainment of new and enhanced physical properties. Improved insight into the principles of how to best create ordered block copolymer based systems will have broad applicability to a host of emerging technologies. Key to this will be knowledge of how the processing conditions interplay with chemical structure to achieve desirable end states and thus afford superior materials based on BCPs.Rod/coil BCPs and their blends with both coil- and rod-homopolymers are largely unexplored and present an opportunity to learn about the role of liquid crystallinity on microphase separation. Emphasis will be on rod/coil - coil blends to investigate rod BCP micelles, and on the presence of reactive groups on the rod block to provide means for locking-in morphologics, for tuning substrate interaction, and to create synthetic anistropic organic nano-objects, which can then be employed as unique building blocks in hierarchical self assembly. Self assembled nanocomposites based on polymer-inorganic materials with magnetic field tunable optical properties will be produced by spatially templating superparamagnetic nanoparticles in BCPs. Surface engineering nanoparticles will be sequestered in the BCP and should display superior properties over the corresponding bulk materials due to their small size (single domain particles). By choosing a BCP that has sufficient molecular weight so that the microdomains' periodicity provides a visible wavelength photonic ban gap (PBG), these researchers will fabricate a magnetic field tunable PBG materials. Such materials have potential as polarization rotators and optical isolators ("one way light valves") via the field dependent Verdet constant of the composite. In addition, the experimental data set of nanoparticle-BDP morphologies will be used to compare to recent theoretical models of the geometry of nanoparticle-BCP self-assembly.This project has several ways to impact society. Visits of graduate students to other universities and to industry are envisioned to give them a broader experience, as well as to access to novel instrumentation. The PI has several highly productive collaborations: C. Ober and S. Gruner (Cornell) - block copolymer synthesis and synchrotron scattering (routine visits by 3-4 students to CHESS and short (one week) periods to Ober lab; S. Margel (Var-Llan, Israel) - nanoparticle synthesis (due to the present situation in Israel, no students have yet visited his lab) and B. Lotz Strasbourg) - TEM and electron diffraction characterization (month long visit to CNRS). The PI has recent experience co-founding a start up (Omni Guide Communications, Inc.) with another professor and a former graduate student, affording a perspective on how to undertake tech transfer from the university into the market place. Over the past 12 years, the PI has filed a total of 15 patent disclosures and 5 patents have been issued. In addition, the PI's group has always hosted several undergraduates, called UROPs, at MIT. Their successful participation in research is attested by co-authorzship of several publications.