Hydrodynamic properties of gelatin in dilute solutions

Aggregation properties of Gelatin chains in neutral aqueous solutions, are reported in the temperature range T = 35-60 degrees C, from the measured intrinsic viscosity [eta], diffusion coefficient, D(o), molecular weight Mw, and radius of gyration (Rg) data. Gelatin chains doubled their size as the solution was cooled to 35 degrees C from 60 degrees C. The intermolecular interaction was found to be repulsive which showed significant decrease as the temperature was reduced. The data provides excellent fitting to the scaling relations Mw[eta] = (1.96 +/- 0.06) x 10(-26)(Re,eta/Re,D)3(D(o) eta o/T)-3 and (D(o)n1/2)-1 approximately equal to (6 1/2 pie eta o chi beta/kB/T)[1 + 0.201(v/beta 3)n1/2] where n is the number of segments in the chain. The ratio of the hydrodynamic radius (Re,D) (deduced from D(o)) and Rg, (Re,D/Rg = zeta) was found to be 0.555. From the known solvent viscosity eta o, the segment length beta, was deduced to be (15 +/- 2) A. The deduced excluded volume was v approximately equal to (4.1 A)3. The Flory-Huggins interaction parameter (zeta) did not show observable temperature dependence.