Phase Behavior and Nanoscale Morphology of Multiblock Copolymers and Biological Gels

本研究的重点是应用散射技术，利用小角中子散射(SANS)、小角X射线散射(SAXS)、原子力显微镜(AFM)和计算机模拟等方法研究多嵌段共聚物在选择性溶剂中的有序-无序和有序-有序相变的相行为和动力学。本研究的重点将是利用基于同步加速器的时间分辨SAXS来跟踪结构特征的时间演化，并将其与无序-有序转变的成核和生长动力学以及不同有序状态之间的转变的理论模型联系起来。我们还将开始使用原子力显微镜成像的初步研究，以表征这些微相分离材料的薄膜的表面形貌。拟议的研究将对这些不同转变中涉及的相分离机制的动力学以及涉及胶束生长本身的机制提供详细的洞察。了解多嵌段共聚物溶液和凝胶的相行为对于它们在材料科学和技术中的大量应用非常重要。一个令人兴奋的潜在应用是将它们用作固态设备纳米光刻的模板。所提出的嵌段共聚物膜的AFM和SAXS研究直接关系到这些膜在纳米光刻中的潜在应用。这项研究还将在设计和制造用于束线设施的专用部件和具有广泛适用性的数据分析程序方面取得进展。拟议的研究将导致两名研究生(包括一名美国女学生)的博士论文，并为本科生提供研究机会。该项目还涉及与捷克共和国科学家的国际合作。

The overall focus of this research is to apply scattering techniques to examine the phase behavior and kinetics of order-disorder and order-order phase transitions in multiblock copolymers in selective solvents using small angle neutron scattering (SANS), small angle x-ray scattering (SAXS), atomic force microscopy (AFM), and computer simulation methods. A major focus of this research will be to use synchrotron based time-resolved SAXS to follow the time evolution of structural features, and relate them to theoretical models of nucleation and growth kinetics of disorder-order transitions and of transitions between different ordered states. We will also initiate preliminary studies using AFM imaging to characterize the surface morphology of films of these micro-phase separated materials. The proposed research will provide detailed insight into the kinetics of the phase separation mechanisms involved in these different transitions, as well as in the mechanisms involved in the growth of micelles themselves. An understanding of the phase behavior of multiblock copolymer solutions and gels is important to their numerous applications in materials science and technology. An exciting potential application is to use them as templates for nanolithography of solid state devices. The proposed AFM and SAXS studies of block copolymer films have direct relevance to the potential application of these films in nanolithography. The research will also lead to advances in designing and building specialized components for use at beam line facilities and data analysis programs with a wide range of applicability. The proposed studies will lead to the Ph. D dissertations of two graduate students (including one female American student) and provide research opportunities for undergraduates. The project also involves international collaboration with scientists in Czech Republic.