Video- and computer-enhanced light microscopy of three-dimensional colloidal structures

The ability of video- and computer-enhanced microscopy to directly visualize colloidal structures in real time has allowed colloid scientists to discover and characterize many new structures and processes. Low contrast surfactant microstructures are particularly amenable to this technique: Recent applications include the discovery and characterization of vesicles in mixtures of cationic and anionic surfactants, the mapping of the phase behavior of superwetting trisiloxane surfactants, the observation of the effects of counter-ion exchange on the dynamics of vesicle structure, and the characterization of the stability of novel reverse vesicles. The coupling of a video microscope and a digital image processor enables the three-dimensional tracking of colloidal particles. As a result, hydrodynamic radii, particle densities, mobilities, and pair potentials are readily accessible. Image processing techniques also allow us to use colloidal dispersions as simulators of molecular nucleation and growth processes.