Soft Materials: Smart Materials
Wednesday, April 9, 2008
The Soft Materials Discussion Group regularly convenes investigators in the New York region with an interest in soft materials research and development, and provides a forum for scientists, engineers, and other key stakeholders working in academia, industry, and not-for-profit entities to exchange ideas and discuss advances. To ensure impact globally, the meeting proceedings will be disseminated electronically through the Academy's eBriefings program. The interdisciplinary topics include a range of technologically important materials in colloids, polymers, emulsions, liquid and organic crystals, membranes, proteins, cells, and tissue.
Program
Jeffrey Koberstein, Columbia University
Ned Thomas, Massachusetts Institute of Technology
Jeffrey T. Koberstein, Columbia University
There are a number of challenges associated with the general implementation of soft material nanotechnology and these challenges are especially important in the field of surface modification. First, one requires a set of rules for the molecular design of surfaces at the nanoscale, second, one needs a method to fabricate the surface that is designed, and third, if the surface is to be responsive in any way, some latent energy source must be incorporated into the material design. This presentation will describe a practically feasible framework we have developed for the molecular design and fabrication of polymer/material surfaces that enable nanoscale manipulation of the chemical groups that reside there. The methods are based upon three-component heterobifunctional molecules designed to self-assemble at the surfaces of both hard and soft substrates. The molecules either present a controlled areal density of reactive functional groups, in our case, alkyne or azide groups capable of Sharpless "click" chemistry, or are preprogrammed with photoactive functionalities that can be activated using only light as a reagent. In some cases, monomolecular surface layers are fabricated by adsorption from supercritical fluids, a process that is applicable to substrates of arbitrary shape. Because light is used to effect surface functionalization, surface patterns of reactive chemical groups can be made directly by illumination through a mask, without the necessity of indirect techniques like stamping. The surface modification strategies developed are extremely versatile for the general modification of surfaces as well as for spatial patterning of a variety of synthetic and biological molecules. Examples presented include using light to spatially control polymer dewetting and to construct the first covalently immobilized carbohydrate microarrays, and using "click"chemistry and spin coating to immobilize DNA with controlled areal density.
Periodic Block Polymeric Materials for NanoTechnology
Ned Thomas, Massachusetts Institute of Technology
Nanotechnology requires control of materials from the atomic to the 100 nanometer to the macroscopic level. Exploiting the size and shape dependence of material properties and accessing multi-functionality holds great promise for the development of materials that will contribute to novel future technologies. Block polymers are a class of materials that have a very broad range of properties and moreover, can act as hosts for metallic and dielectric nanoparticles as well as organic molecules, resulting in nanocomposites with combinations of properties not available by other means. Periodic structural assemblies are of particular interest, due to their interesting interactions with waves: especially electromagnetic and mechanical waves.