Materials World Network: Triblock Terpolymers for Self-Assembled Nanolithography

两嵌段共聚物自组装成特征尺寸通常为10-50 nm的周期性微区阵列，已被用作自组装抗蚀剂。定义在制造各种器件(如硅电容器和晶体管、光子晶体和图案化磁性介质)中有用的周期图案。然而，两嵌段共聚物中的层状、圆柱状或球状微区通常形成格栅图案，或具有六方对称性的紧密堆积结构。这限制了它们的设备应用，使得人们希望创建具有更广泛的几何和应用范围的自组装图案。为了克服这一限制，麻省理工学院(MIT)和英国布里斯托尔大学的这一合作项目将开发三嵌段三元共聚物，形成具有不同几何形状的薄膜。这项工作包括设计三嵌段三元共聚物以形成具有特定几何形状的薄膜，如宽或近距离的直线、具有特定边缘调制、结或弯曲的直线、或非紧密堆积排列的圆柱体或球体阵列；合成具有适当嵌段化学、相互作用和体积分数的聚合物；了解包括衬底处理和热处理工艺在内的加工效应；对自组装进行建模；以及在一个嵌段内生成磁性纳米颗粒，以直接形成功能性纳米结构。这项工作的中心是利用衬底化学和拓扑学研究三嵌段三元共聚物的模板，以便自组装可以被引导到纳米级的精度。学生将在国际环境中接受培训和指导，包括三嵌段三元共聚物的合成化学，嵌段共聚物光刻和模板，以及功能纳米结构的制造。调查人员将合作编写教材，包括关于自我组装的讲座和演示，并通过学校和社区大学的外联活动以及利用麻省理工学院开放课程计划等资源向广泛受众传播这项工作。

Diblock copolymers self-assemble into periodic arrays of microdomains with feature sizes of typically 10-50 nm, and have been used as self-assembled ?resists? to define periodic patterns useful in making a wide range of devices such as silicon capacitors and transistors, photonic crystals, and patterned magnetic media. However, the lamellar, cylindrical or spherical microdomains in diblock copolymers generally form grating patterns, or close-packed structures with hexagonal symmetry. This restricts their device applications, making it desirable to create self-assembled patterns with a wider range of geometries and applications. To overcome this limitation, this collaborative project between the Massachusetts Institute of Technology (MIT) and the University of Bristol in the United Kingdom will develop triblock terpolymers which form thin films with a diverse range of geometries. The work includes design of triblock terpolymers to form films with specific geometries such as widely or closely-spaced lines, lines with specific edge modulations, junctions, or bends, or arrays of cylinders or spheres in non-close-packed arrangements; synthesis of polymers with appropriate block chemistry, interactions and volume fractions; understanding processing effects including substrate treatment and annealing processes; modeling the self-assembly; and generation of magnetic nanoparticles within one block to form functional nanostructures directly. Central to this work is an investigation of templating of triblock terpolymers using substrate chemistry and topography, so that the self-assembly can be guided to nanoscale precision.Students will be trained and mentored in an international setting, including the synthetic chemistry of triblock terpolymers, block copolymer lithography and templating, and the fabrication of functional nanostructures. The investigators will collaborate on developing teaching materials including lectures and demonstrations on self-assembly, and on dissemination of this work to a wide audience through school and community college outreach and use of resources such as the MIT OpenCourseWare initiative.