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Papers by gerardo ternero

Journal of Polymer …, 1994

A method which allows the evaluation of phenomenological ion exchange constants K,, is proposed a... more A method which allows the evaluation of phenomenological ion exchange constants K,, is proposed and tested in a cationic polyelectrolyte system. Results for nitrate/chloride exchange are nearly constant over the entire concentration range studied. However, for nitrate/ bromide exchange, the results depend on the polyelectrolyte concentration, with K,, following the same trend as the mean activity coefficient for the polyion bromide. For polyion fluoride, a conformational change is probably induced as nitrate is added to the solution and the result deviates from the linear relationship predicted by the method. Benzene sulfonate behaves like a hydrophilic anion, whereas tosylate and ethylbenzene sulfonate also induce conformational changes by hydrophobic interactions. These results are supported by viscosity measurements and agree well with those recently reported by Satoh, who considered changes in apparent molar volume.

Journal of Polymer Science …, 1991

The mean ion activity coefficient, (Y +)~~/ (y,)9,,11 for different high-linear charge density ca... more The mean ion activity coefficient, (Y +)~~/ (y,)9,,11 for different high-linear charge density cationic polyelectrolyte fluoride, bromide, chloride and nitrate has been determined. The order found is: F > NO 1. The results obtained with added nitrate were compared with those predicted by Iwasa, Guhron, and Weisbuch and Manning's models. The latter presents the hest agreement for polyion chloride and bromide. It was possible to establish the most probable microconfiguration for the polyions studied here. Manning's theory gives a moderate agreement for polyion fluoride values compatible with a lower charge density than for polyelectrolyte chloride and hromide.

Journal of Polymer Science …, 1991

The mean ion activity coefficient, (Y +)~~/ (y,)9,,11 for different high-linear charge density ca... more The mean ion activity coefficient, (Y +)~~/ (y,)9,,11 for different high-linear charge density cationic polyelectrolyte fluoride, bromide, chloride and nitrate has been determined. The order found is: F > NO 1. The results obtained with added nitrate were compared with those predicted by Iwasa, Guhron, and Weisbuch and Manning's models. The latter presents the hest agreement for polyion chloride and bromide. It was possible to establish the most probable microconfiguration for the polyions studied here. Manning's theory gives a moderate agreement for polyion fluoride values compatible with a lower charge density than for polyelectrolyte chloride and hromide.

Journal of Polymer …, 1994

A method which allows the evaluation of phenomenological ion exchange constants K,, is proposed a... more A method which allows the evaluation of phenomenological ion exchange constants K,, is proposed and tested in a cationic polyelectrolyte system. Results for nitrate/chloride exchange are nearly constant over the entire concentration range studied. However, for nitrate/ bromide exchange, the results depend on the polyelectrolyte concentration, with K,, following the same trend as the mean activity coefficient for the polyion bromide. For polyion fluoride, a conformational change is probably induced as nitrate is added to the solution and the result deviates from the linear relationship predicted by the method. Benzene sulfonate behaves like a hydrophilic anion, whereas tosylate and ethylbenzene sulfonate also induce conformational changes by hydrophobic interactions. These results are supported by viscosity measurements and agree well with those recently reported by Satoh, who considered changes in apparent molar volume.

Journal of Polymer Science …, 1991

The mean ion activity coefficient, (Y +)~~/ (y,)9,,11 for different high-linear charge density ca... more The mean ion activity coefficient, (Y +)~~/ (y,)9,,11 for different high-linear charge density cationic polyelectrolyte fluoride, bromide, chloride and nitrate has been determined. The order found is: F > NO 1. The results obtained with added nitrate were compared with those predicted by Iwasa, Guhron, and Weisbuch and Manning's models. The latter presents the hest agreement for polyion chloride and bromide. It was possible to establish the most probable microconfiguration for the polyions studied here. Manning's theory gives a moderate agreement for polyion fluoride values compatible with a lower charge density than for polyelectrolyte chloride and hromide.

Journal of Polymer Science …, 1991

The mean ion activity coefficient, (Y +)~~/ (y,)9,,11 for different high-linear charge density ca... more The mean ion activity coefficient, (Y +)~~/ (y,)9,,11 for different high-linear charge density cationic polyelectrolyte fluoride, bromide, chloride and nitrate has been determined. The order found is: F > NO 1. The results obtained with added nitrate were compared with those predicted by Iwasa, Guhron, and Weisbuch and Manning's models. The latter presents the hest agreement for polyion chloride and bromide. It was possible to establish the most probable microconfiguration for the polyions studied here. Manning's theory gives a moderate agreement for polyion fluoride values compatible with a lower charge density than for polyelectrolyte chloride and hromide.