Correlation length and amplitude scaling in critical polymer solutions

We present a light scattering measurement of the correlation length for a s eries of critical solutions of polystyrene in methylcyclohexane with differ ent molecular weights. Our results show that the correlation length xi simi lar to N(zeta)nu epsilon(-0.63), where N is the polymerization index and ep silon =(T-T-c)/T-c is the reduced temperature. The N exponent zeta(nu) is f ound to be 0.18+/-0.02, which is contrary to most earlier direct experiment al results but in excellent agreement with theoretical predictions by de Ge nnes and Stepanow. (C) 1999 American Institute of Physics. [S0021-9606(99)5 1142-2].