CAREER: Polymer Langmuir Monolayers: Boundaries, Dynamics and Thermodynamics

本项目的目的是研究朗缪尔薄膜在空气/水界面的界面张力和表面粘度，并确定如何控制朗缪尔单分子膜的结构和动态响应。当分子在表面上排列时，对称性被破坏，导致表面分子之间的远程静电斥力。单层内的运动耦合到衬底。流体力学和静电学的结合导致了薄膜中的长寿命亚稳态。这些态的形成和由此产生的弛豫决定了生物膜的结构和动力学，并且对制备朗缪尔-布洛杰特薄膜至关重要。本项目将重点研究作为单层膜的致密、相分离聚合物的孤立孤岛的流变学。边界张力将被确定为温度和分子质量等各种参数的函数，并将结果与理论和数值结果进行比较。对于共聚物，我们将探索液晶侧链在增加分数时对界面能和结构的影响。一个主要的教育目标是在每个教育水平上吸引和培训不同的学生群体，并鼓励跨学科合作，解决基础科学中的重要技术问题。%的朗缪尔薄膜由自限制在流体表面的分子组成，用作技术和生物重要系统的准二维模型系统，如泡沫、乳剂、朗缪尔-布洛吉特多层膜和生物膜。当控制充分时，朗缪尔-布洛杰特薄膜可用作液晶取向层、非线性光学薄膜和模拟生物膜。

The aim of this project is to investigate the boundary tension and surface viscosity of Langmuir films at the air/water interface, and to determine how to control the structure and dynamic response of Langmuir monolayers. When molecules align at a surface, symmetry is broken leading to long -range electrostatic repulsion between surface molecules. Movement within the monolayer is coupled to the substrate. The combination of hydrodynamics and electrostatics leads to long lived metastable states within the film. The formation of these states, and the relaxation from them, determines the structure and dynamics of biomembranes and are crucial in making Langmuir-Blodgett films. This project will focus on the rheology of isolated islands of dense, phase-separated polymers as monolayer films. The boundary tension will be determined as a function of various parameters such as temperature and molecular weight, and the results compared with theoretical and numerical results. With copolymers, the influence of liquid crystal side chains in increasing fractions on the boundary energy and structure will be explored. A major educational goal is to attract and train a diverse group of students at every educational level, and to encourage interdisciplinary collaborations in addressing the fundamental science of technologically important questions.%%%Langmuir films consisting of molecules self-confined at a fluid surface serve as model quasi-two dimensional systems of technologically and biologically important systems such as foams, emulsions, Langmuir-Blodgett multilayers, and biological membranes. Langmuir-Blodgett films, when sufficiently controlled, are used as liquid crystal alignment layers, as films for non-linear optics, and for modeling bio-membranes.