Charge transfer interactions. Part II. Usefulness of multiangle laser light scattering studies

As an absolute method, which does not require standard substances to obtain the molecular weights of a specific polymer, the laser light scattering is an under-exploited method for study of polymers behavior in solution. Therefore, in this study, the variation of physico-chemical parameters in solution of polymers from poly(N-vinylcarbazole)/2,2'4,4'-tetranitrodibenzyl (PVK-TNDB) and poly(N-ethyl-3-hydroxymethyl phenothiazinyl methacrylate)/poly(beta-hydroxyethyl-3,5-dinitrobenzoate methacrylate) (PEHMPtM-PHEDNBM) systems was analyzed by multiangle laser light scattering (MALLS) and correlated with their ability to interact by charge transfer (CT). The confirmation of charge transfer interactions even in solid state was realized by atomic force microscopy (AFM) or differential scanning calorimetry studies (DSC). In case of PVK-TNDB mixtures, two variants for approximation of experimental MALLS data were tested. The Zimm plot and Berry formalism were used, but first- or second-order fitting of the experimental data by scattering angles, theta, were compared. In both cases, the maximum values of weight averaged molecular weight, (M) over bar (w), and radius of gyration, R-g, for polymer were recorded for 1/1 molar ratio, even that with the second-order fitting these values were overestimated. In solid state, the AFM imaging has shown good compatibility between PVK and TNDB based on charge transfer interactions, preserved after solvent evaporation. In case of PEHMPtM-PHEDNBM mixtures, the maximum number of CT interactions was established for equimolar ratio of components both in solution, where a maximum value for weight average molecular weight and in solid state for glass transition temperature, respectively were foud.