ELECTRICAL CONDUCTIVITY OF HYDROPHOBICALLY MODIFIED POLYELECTROLYTES IN METHANOL/WATER SOLUTION
Measurements of the electrical equivalent conductivity of potassium salts of poly(maleic acid-co-1-olefins), PA-nK2 with n = 12, 18 has been carried out in methanol-water mixtures in the whole range of composition. The relative interaction parameter f*, was determined as a function of the mole fract...
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| Auteurs principaux: | , , , |
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| Langue: | English |
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Sociedad Chilena de Química
2003
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| Accès en ligne: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072003000100012 |
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| Résumé: | Measurements of the electrical equivalent conductivity of potassium salts of poly(maleic acid-co-1-olefins), PA-nK2 with n = 12, 18 has been carried out in methanol-water mixtures in the whole range of composition. The relative interaction parameter f*, was determined as a function of the mole fraction of methanol. The values of f* do not follow the same tendency of the limiting equivalent conductivity. This unusual behavior was rationalized in terms of a methanol-induced conformational transition that takes the polymer chain from a compact to an expanded structure. As a consequence of this transition the average charge distance in the polyion increases with increasing mole fraction of methanol. This brings about a decrease of the linear charge density parameter, and therefore an increase of the fraction of polymer charges dissociated from their counterions. The existence of the conformational transition of the PA-nK2 copolymers was confirmed through fluorescence probing experiments |
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