Braun Group Research Summary

Our research program covers a wide range of materials science disciplines, with a general focus on the formation and study of nano and microstructures through self and directed assembly. Materials containing structure on these length scales have been found to exhibit interesting and important electrical, optical, mechanical and biological properties. We often use and develop new materials chemistry and self-assembly approaches for the synthesis of these materials, which allows us to create novel structures and materials including photonic band gap structures, conducting polymers , nanostructured ceramics, semiconductors, biomaterials and thermoelectric materials. In other projects in our group, we are investigating molecular transport in confined geometries, self-healing polymers and the synthesis of functionalized nanoparticles.

An important component of our research is the formation and characterization of photonic band gap structures. Structures exhibiting photonic band gaps have very interesting and potentially important optical properties. For example, waveguides formed from photonic band gap materials can execute a 90 degree turn over a few microns, which is necessary for the on-chip integration of optical devices. One way to form the periodic structure necessary to realize a photonic band gap is through templating with self-organized colloidal crystals. We are developing new routes to the formation of such structures, as well as new techniques for the writing of defined defect structures in photonic crystals.

An example of a nanostructured system we study is liquid crystals, which can be designed to contain periodic structure ranging from one nanometer to greater than 100 nanometers. The liquid crystal mediated synthesis of materials could provide many yet unseen properties. Liquid crystal mediated synthesis of materials is a new field, and very few of the basic principles are known or understood. We are attempting to quantify the important parameters, such as the liquid crystal – product interaction, and the effect of the liquid crystal’s structure. In one project, for example, we are studying the use of liquid crystal nanoreactors to synthesize bismuth nanoparticles for thermoelectric applications.