The correlation length amplitude for eight-arm star polystyrene in methylcyclohexane near the critical point

The turbidity of eight-arm star polystyrene in methylcyclohexane has been measured and used to determine the correlation length amplitude xi0 for different molecular weight polystyrene. The turbidity in this system was determined from the measured ratio of the transmitted to incident light intensities over three decades in reduced temperature. Using Ornstein-Zernike theory, we are able to fit the turbidity data and determine that xi0 increases systematically for this branched polystyrene in much the same way as a linear polystyrene of the same molecular weight. We acknowledge the support from NSF-REU grant DMR 0243811 and the donors of the American Chemical Society Petroleum Research Fund.