Controlled manipulation of engineered colloidal particles

This research utilized the Particle Replication in Non-wetting Templates (PRINTRTM) technology to fabricate highly tailored colloidal particles. The behavior of these engineered particles were studied as they were subjected to different precisely controlled external influences, including electric fields, magnetic fields and a templating approach based on the PRINT process. Given the tunability in particle properties afforded by the PRINT process, exceptional control of the resulting particle assemblies and particle mobility were observed, suggesting potential applications in numerous materials and life science applications that require control on the nanoscale.;As the PRINT process was integral to all aspects of this research, it was important to gain a clear understanding of mechanism by which perfluoropolyether (PFPE) elastomeric molds can generate monodisperse arrays of discrete, uniform particles with tailored size, shape and composition. Thus, fundamental studies were conducted on the PFPE elastomers, focusing on contact mechanics measurements and capillary flow experiments. The results confirmed the low surface energy of PFPE, an important property that renders the PFPE molds ideal for the PRINT process. Capillary flow experiments were conducted to study the method by which PFPE molds can be filled during the PRINT process. The flow in closed PFPE microchannels was compared to that in PDMS and glass.;Suspensions of PRINT particles were studied in the presence of electric and magnetic fields. Electric field experiments were conducted using non-uniform alternating current electric fields and uniform direct current electric fields. Magnetic field experiments were conducted using both stationary and rotating magnetic fields. Particle assemblies were observed to form and could be tuned by particle shape and composition. Particle motion, both translational and rotational, was also controlled. Properties were found to be both shape and composition dependent. These experiments were applied to the fabrication of steerable micromotors and the driving of deformable particles through confined environments.;Using the inherent templating nature of the PRINT process, highly ordered polymer composite films were fabricated to completely avoid particle aggregation. The fabrication process was optimized for different compositions and film nanostructures. These experiments were applied to the fabrication of dielectric composite films for capacitors.