The essence of nanotechnology is the ability to work at the molecular level to create large structures with fundamentally new molecular organization.  Materials with features on the scale of nanometers often have properties different from their macroscale counterparts.  Important among nanoscale materials are nanohybrids or nanocomposites, materials in which the constituents are mixed on a nanometer-length scale.  They often exhibit properties superior to conventional composites, such as strength, stiffness, thermal and oxidative stability, barrier properties, as well as unique properties like self-extinguishing behavior and tunable biodegradability. 
         Another unique aspect of nanocomposites is the lack of properties trade-offs.  For the first time, there is an opportunity to design materials without the compromises typically found in conventionally filled polymer composites.  Uses for this new class of materials can be found in aerospace, automotive, electronics and biotechnology applications, to list only a few.  
        Though significant progress has been made in developing nanocomposites with different polymer matrices, a general understanding has yet to emerge.  For example, what allows nanocomposites to be both stiffer and tougher than conventional composites, without sacrificing other properties?  Why do they display better thermal stability versus unfilled polymers?  How can we utilize specific molecular interactions to control structure and morphology?  How can materials properties be predicted from the nanostructure and dynamics?  A major challenge to further development of nanocomposites is the lack of even simple structure-property models. Without such models, progress in nanocomposites has remained largely empirical.  Similarly, predicting ultimate materials properties or maximum theoretical performance for different classes of nanocomposites is almost impossible at present. 
        At Cornell, our group has been focusing on several fronts ranging from new synthetic approaches to characterization and modeling.   Our objective is to build an understanding that will permit the prediction and control of nanocomposite properties.