Morphological control of mesoscale colloidal models

Colloidal systems have proven useful mesoscale models because of their relatively large size, slow dynamics, and the ease with which one can alter the interactions between individual particles. Studies of these systems are often conducted by varying the effective pair potential and then studying the resulting morphologies through microscopy or scattering techniques. Using optical-based manipulation methods, however, one can directly assemble colloidal morphologies of interest. By spatially modulating laser-light intensity with a single scanning laser, we have been able to create optical traps of arbitrary design and construct colloidal structures of very specific morphology. In addition, once trapped, we have been able to lock in these structures using polymerization techniques. Our goal is to use this approach to both help us understand fundamental thermodynamic processes and to create templates for morphologies which would not otherwise develop. (C) 2001 Elsevier Science B.V. All rights reserved.