Solvation of certain N-based polycationic electrolytes: viscosity measurements in dimethylformamide and dimethylsulfoxide

Viscosities of four new types of polycationic electrolytes possessing N-alk yl/N-acylammonium and 2,5-thiophenylene linkages in their respective repeat ing units of the chain (Mol. Wt. 1154-3815) have been studied in the two di polar aprotic solvents viz., dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The data obtained in DMSO were treated on the basis of Fuoss-Straus s equation. The maximum in reduced viscosity vs concentration profile and t he validity of extrapolation procedure to obtain intrinsic viscosity, [eta] ((eta(sp)/C)c=o) were discussed on account of solvation models involved. T he concept of critical overlap concentration in collaboration with the deri ved parameters such as characteristic ratio (C-infinity), maximum cross-dim ension ((S) over bar), root mean square end-to-end distance (<Rg(2)>(1/2)) and plane projection distance (P) was invoked to comprehend polycationic hy drodynamic models in the two solvents of intermediate permittivity at 25+/- 5 degrees C. (C) 1999 Elsevier Science B.V. All rights reserved.