Optical Properties of Polymer Particles used for Contrast Variation studies of Phase Transitions

摘要

Suspensions of poly-methylmethacrylate (PMMA) particles coated with a thin layer of poly-12-hydroxystearic acid (PHSA) have been used for contrast variation studies of phase transitions by varying the relative amounts of two appropriate solvents. However, this method has a number of drawbacks. Recently, the standard preparation method for PMMA was modified by including tri-fluoroethylacrylate (TFEA) as a copolymer so that the particles have the same refractive index as cis-decalin. We have optically characterised these particles, and analysed the results in terms of a simple core-shell model. These new particles are ideal for contrast variation studies of phase transitions in concentrated binary mixtures.