Creation of Nanoscopic Structures at Various Interfaces

影响两嵌段共聚物纳米几何形状的变量将被考察在液-气、固-气和固-液界面上的各种两亲两嵌段不对称。因为双嵌段的特征往往是分子尺度的，所以观察到的尺寸自然落在纳米范围内。这项工作的一个方面是使用Langmuir-Blodgett(LB)槽在硅衬底上控制沉积两嵌段共聚物，其中表面密度是一个可选择的参数。两亲双嵌段的不同不对称性由于水不溶嵌段的聚集而产生不同的形貌。作为对LB研究的补充，将使用衰减全反射模式(FTIR-ATR)中的傅立叶变换红外光谱(FTIR-ATR)，在高于和低于临界胶束浓度(CMC)的溶液浓度下，确定从各种溶剂吸附到液-固界面的相同选择的双嵌段的动力学和表面过剩。原子力显微镜、中子反射率和椭偏测量法将有助于解释表面过剩和三维结构。这些方法的结合应该可以更好地理解可以用来控制表面密度和几何形状的热力学和动力学参数。研究项目的参与者将包括一名博士后研究员和几名本科生。此外，目前与当地一所高中的互动将随着高中生的研究机会和更多的互动和后续体验而得到加强。将继续开发一门表面结构和光谱学高级课程，以便在教学中利用新技术。

The variables affecting the nanoscopic geometry of diblock copolymers will be examined for a variety of amphiphilic diblock asymmetries at the liquid-air, solid-air and solid-liquid interfaces. Because the features of diblocks tend to be molecular in scale, the sizes observed naturally fall into the range of nanometers. One aspect of this work focuses on the controlled deposition of diblock copolymers on silicon substrates using a Langmuir-Blodgett (LB) trough, where the surface density is a selectable parameter. Different asymmetries of an amphiphilic diblock have produced various morphologies due to aggregation of the water-insoluble block. In a complementary fashion to the LB studies, the kinetics and surface excess of the same selection of diblocks adsorbed from a variety of solvents to a liquid-solid interface will be determined for solution concentrations above and below the critical micelle concentration (cmc) using Fourier Transform IR spectroscopy in the mode of attenuated total reflection (FTIR-ATR). Atomic Force Microscopy neutron reflectivity and ellipsometry will aid in the interpretation of surface excess and three-dimensional structure. The combination of these approaches should provide a better understanding of the thermodynamic and kinetic parameters that can b used to control surface density and geometry.%%%Participants in the research projects will include a postdoctoral researcher and several undergraduates. In addition, the current interaction with a local high school will be enhanced with a high school student research opportunity and more interactions and follow-up experiences. An advanced course in Surface Structure and Spectroscopy will continue to be developed in order to take advantage of new technologies in education.