Field-aided micro-tailoring of polymeric nanocomposites

Contemporary applications could benefit from multifunctional materials having anisotropic optical, electrical, thermal or mechanical properties. These desirable features, but with locally-controlled distribution of directional response, would be even more attractive. Such materials are difficult to engineer by conventional methods. However, the field-aided technology presented herein is able to locally tailor electroactive composites. By applying an electric field to a polymer in its liquid state, we have developed ability to orient chain- or fiber-like inclusions or phases from what was originally an isotropic material. Such composites can be formed from liquid solutions, melts, or mixture of pre-polymer and cross-linking agent. Upon curing, a "created composite" results consisting of these "pseudo fibers" embedded in a matrix. One can also create orientated composites from embedded spheres, flakes or fiber-like shapes in a liquid plastic. Orientation of the externally applied electric field defines the orientation of field-aided self-assembled composites. The strength and exposure duration of the electric field control the degree of created anisotropy. Results of electromechanical testing of these modified materials relevant to sensing and actuation applications are presented. Material microstructure is analyzed using microscopy and X-ray diffraction. The performance of these novel materials having different composition and morphology is being investigated.