Creation of Nanoscopic Structures at Various Interfaces

Harvey Mudd College, Claremont CA

Investigators

Abstract

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.