Materials World Network: Triblock Terpolymers for Self-Assembled Nanolithography

双嵌段共聚物自组装成微畴的周期性阵列，其特征尺寸通常为10-50 nm，并已被用作自组装的抗蚀剂。定义用于制造各种器件的周期图形，如硅电容器和晶体管、光子晶体和图像化磁介质。然而，双嵌段共聚物中的层状、圆柱形或球形微畴通常形成光栅图案，或具有六边形对称的紧密排列结构。这限制了它们的设备应用，使得需要创建具有更广泛几何形状和应用的自组装模式。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之间的合作项目将开发三嵌段三元聚合物，这种聚合物可以形成具有多种几何形状的薄膜。工作包括设计三嵌段三元聚合物，以形成具有特定几何形状的薄膜，例如宽间距或紧密间距的线条，具有特定边缘调制的线条，结或弯曲，或非紧密排列的圆柱体或球体阵列；具有适当的嵌段化学、相互作用和体积分数的聚合物的合成；了解加工效果，包括衬底处理和退火工艺；自组装建模；并在一个块内产生磁性纳米颗粒，直接形成功能纳米结构。这项工作的核心是利用衬底化学和地形对三嵌段三元聚合物的模板化进行研究，以便将自组装引导到纳米级精度。学生将在国际环境中接受培训和指导，包括三嵌段共聚物的合成化学，嵌段共聚物光刻和模板，以及功能纳米结构的制造。研究人员将合作开发教学材料，包括自我组装的讲座和演示，并通过学校和社区学院的外展和使用麻省理工学院开放课程计划等资源，将这项工作传播给广泛的受众。

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.