DIMENSIONAL AND HYDRODYNAMIC FACTORS FOR FLEXIBLE STAR POLYMERS IN THE GOOD SOLVENT LIMIT

Star chains composed of arms with uniform length were generated on a s imple cubic lattice by the Monte Carlo method using the enrichment alg orithm, which enabled us to obtain chains with total segment numbers ( N) up to 1200. The number of arms (f) ranged from 2 to 24. The radius of gyration ([S-2](1/2)), the dimensionless intrinsic viscosity (E), a nd the hydrodynamic radius (R-H) were evaluated as functions off and N by averaging over more than 4000 samples. The calculations of E and R -H were made according to Zimm's method. It was found that the radius expansion factor (alpha(s)) for Star chains with long arms obeys the r elation alpha(s)(2) = 1.53z(2/5), which is known for long flexible lin ear chains, where z is the excluded volume parameter. The ratios of [S -2], E, and R-H Of star chains to those for Linear chains were evaluat ed as functions off. These ratios obtained and the Flory factors for t he intrinsic viscosity and R-H extrapolated to N-1/2 --> 0 reproduced experimental data well.