Rayleigh linewidth data has been gathered from a 1.9 micron film of a 2,6-lutidine+water critical mixture, taken at a scattering angle of ten degrees. We have modified our heterodyne autocorrelation spectrometer, used for studies of the dynamic response of critical fluid films, to enable us to measure the intensity autocorrelation of light scattered at forward angles. Stable black bilipid membranes have been produced, both spherical and planar, with and without embedded microparticles. The authors have made progress toward the development of a computer processed array detector-spectrometer to be used in studies of melting and crystallization of two dimensional colloidal particle films. The authors have found that the aggregates formed, when a colloidal particle monolayer coagulates following switching off of the repulsive electric dipole-dipole interactions, show scale invariance with a fractal dimension more ยป consistent with the prediction of a theory of diffusion limited aggregation in two dimensions. A phase transition to a close packed triangular lattice phase occurs at very high densities, when the attractive van der Waals/steric interations between particles dominate. The crystals deform elastically as the crystals are compressed in a Langmuir trough from a lattice spacing of ten microns to spacings less than two microns. The authors have studied the response to compression of colloidal particle crystals in monolayers on the surface of water.
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