MEAN-SQUARE RADIUS OF GYRATION AND HYDRODYNAMIC RADIUS OF JOINTED STAR (DUMBBELL) AND H-COMB POLYMERS

Equations for the mean square radius of gyration and the hydrodynamic radius for jointed stars (dumbbells) and H-combs are derived, based on random flight statistics for each subchain. Comparison with literatur e data on computer simulations and experimental data for H-combs show good agreement for the g-value of the mean square radius of gyration e ven in good solvents. This suggests that for the mean square radius of gyration the relative dimension of a H-comb relative to the linear mo lecule of the same degree of polymerization is not altered significant ly by long range interactions, as in the case of star polymers. For th e hydrodynamic radius the situation is different. Fair agreement is fo und when comparing our results with viscosity measurements under theta conditions, while in good solvents the viscosity of the branched mole cule is more reduced than predicted by our results.