Directed Self Assembly of Triblock Terpolymer Films

非技术概要：嵌段共聚物是一类聚合物材料，其分子可以从溶液中浇铸形成复杂的、规则的三维内部结构，称为微畴。这些微畴的尺寸可以达到几纳米（一米的十亿分之一）以上，它们的几何形状和化学性质可以通过嵌段共聚物的设计来控制。大多数工作都集中在具有两种类型微域的嵌段共聚物上，但本项目研究了同时存在三种不同类型微域的嵌段共聚物的行为，产生了广泛的复杂几何形状。它研究了在这些材料的薄膜中形成不同排列的微畴的条件，并展示了它们的技术用途，特别是对于半导体器件制造，其中微畴模式可用于定义比传统制造工艺更小的特征。这可能允许未来的设备缩放到更高的密度，生产更便宜、更快的存储器或微处理器。其他应用包括催化或过滤，其中表面需要具有特定的化学性质或孔隙度。这项工作将涉及研究生和本科生在一个跨学科的环境中结合实验和理论。拓展将包括创建在线学习材料，为教师和社区大学生提供暑期项目，以及剑桥科学节的公共活动。技术概述：嵌段共聚物微相分离成周期性纳米级结构，使其成为包括纳米光刻和过滤在内的一系列应用的候选者。绝大多数关于薄膜嵌段共聚物的研究都集中在二嵌段共聚物上，但三嵌段三元聚合物（包括线性或星形结构的三个不同嵌段）可以实现更广泛的薄膜形态，包括平铺图案、方形对称图案和90度弯曲结构。提出的工作将展示如何通过聚合物组成和加工条件之间的相互作用来控制三嵌段三元共聚物薄膜的形态，以及如何使用地形衬底特征，使用协调实验和使用自一致场理论的理论研究来模板化特定的形态。三嵌段三元共聚物体积分数、分子结构、相互作用参数、膜厚度、溶剂退火与模板几何和衬底表面化学的结合提供了一个丰富的参数空间，在这个空间内，可以理解微相分离的动力学和热力学，以及技术上有用结构的形成。这项工作的广泛影响源于三嵌段三元聚合物的变革潜力，可以在微电子工业和需要具有特定几何形状的化学非均质表面的领域中产生与纳米光刻和纳米制造相关的纳米级图案。这项工作将涉及研究生和本科生在一个跨学科的环境中结合实验和理论。拓展将包括创建在线学习材料，为教师和社区大学生提供暑期项目，以及剑桥科学节的公共活动。

NON-TECHNICAL SUMMARY: Block copolymers are a class of polymeric materials whose molecules can come together when cast from solution to form intricate, regular three-dimensional internal structures called microdomains. These microdomains can have dimensions of a few nanometers (billionths of a meter) and above, and their geometry and chemistry can be controlled through the design of the block copolymer. Most work has focused on block copolymers with two types of microdomains, but this project examines the behavior of block copolymers in which three different types of microdomain are simultaneously present, producing a wide range of complex geometries. It investigates the conditions under which different arrangements of microdomains are formed in thin films of these materials, and it demonstrates their technological usefulness, in particular for semiconductor device manufacturing, where the microdomain patterns can be used to define features smaller than those available from conventional manufacturing processes. This may allow future scaling of devices to higher densities, producing cheaper and faster memories or microprocessors. Other applications include catalysis or filtration where surfaces are required with particular chemistry or porosity. The work will involve graduate and undergraduate students in an interdisciplinary environment combining experiment and theory. Outreach will include the creation of online learning materials, summer projects for teachers and community college students, and public activities at the Cambridge Science Festival.TECHNICAL SUMMARY: Block copolymers microphase separate into periodic nanoscale structures, making them candidates for a range of applications including nanolithography and filtration. The great majority of work on thin film block copolymers has focused on diblock copolymers, but triblock terpolymers, which include three different blocks in a linear or star architecture, enable a much wider range of thin film morphologies including tiling patterns, square symmetry patterns, and structures with 90 degree bends. The proposed work will show how the morphologies of triblock terpolymer films can be controlled via interplay between the polymer composition and the processing conditions, and how specific morphologies can be templated using topographical substrate features, using coordinated experiments and theoretical investigations using self consistent field theory. The combination of triblock terpolymer volume fractions, molecular architecture, interaction parameters, film thickness, and solvent annealing with template geometry and substrate surface chemistry provides a rich parameter space within which an understanding of the kinetics and thermodynamics of microphase separation as well as the formation of technologically useful structures can be accomplished. The broader impacts of this work originate from the transformative potential of triblock terpolymers to produce nanoscale patterns relevant to nanolithography and nanomanufacturing, both in the microelectronics industry and in fields where a chemically heterogeneous surface with specific geometry is required. The work will involve graduate and undergraduate students in an interdisciplinary environment combining experiment and theory. Outreach will include the creation of online learning materials, summer projects for teachers and community college students, and public activities at the Cambridge Science Festival.