Polymers
The polymers program has a long tradition as a world-class center for the study of structure/property relations in polymers.
The rheology and processing behavior of novel and complex polymeric and colloidal systems are of interest to Professor Khan. Rheological techniques are invaluable for providing information on both the microstructural and processing aspects of such materials. Collaborative efforts between Professors Kelly and Khan are underway to develop biopolymers with controlled molecular architecture. Professor Khan also collaborates with Professor Fedkiw to develop composite polymer electrolytes which decouple the mechanical behavior of the polymer from its conductivity. This research promises to impact the development of efficient and safe rechargeable batteries for use in electric vehicles, camcorders, and laptop computers, and other advanced electronic systems.
Professor Genzer's group studies polymer behavior at surfaces, interfaces, and in confined geometries. His group fabricates novel nanocomposite materials based on organized dispersions of nanoparticles in polymeric matrices. These unique structures can be utilized for future tunable membrane devices, high-density magnetic storage materials, and molecular semiconductors. Professor Genzer's group is also developing experimental and theoretical methods to study interface performance of surfactants and biologically active molecules. In a collaboration with researchers at NIST and Brookhaven National Labs, Professor Genzer's group is probing the chain microstructure in ultra-thin polymer films.
Many practical applications of polymers, such as nanoscale filters, chemical sensors, organic templates, and biomedical/electro-optical devices rely on heterophase polymers in which the size scale of phase separation ranges from a few nanometers to several microns. The research in Professor Spontak's group focuses on the design, characterization, and modeling of such systems through the use of optical, electron, x-ray, and probe microscopies, in addition to small-angle x-ray and neutron scattering. Systems of current interest include block copolymers, organic gels, and polymer blends and foams produced in supercritical CO2.
Block copolymers, like their small-molecule surfactant analogs, order into a wealth of nanoscale microstructures. Shown in this transmission electron microtomograph (3-D TEM image) from Professor Spontak's lab is the L3 "sponge" morphology that develops in a binary blend of a novel A(A/B)B block copolymer and A homo-polymer. It is seen here, for the first time in 3-D, to consist of a randomly connected bilayered membrane, as could only be inferred from small-angle neutron scattering.
