Publicaciones 2011-2020

@article{RN207,
title = {Binding of Phenols with Amphipathic Cationic Polyelectrolytes},
author = { H. Rios and G.A. Collio and M. Urz\'{u}a and V. Vargas},
url = {/brokenurl#<Go to ISI>://WOS:000331602300006},
doi = {10.1080/00222348.2013.845067},
issn = {0022-2348},
year = {2014},
date = {2014-01-01},
journal = {Journal of Macromolecular Science Part B-Physics},
volume = {53},
number = {3},
pages = {428-439},
abstract = {The association of phenols, such as p-cresol, tribromophenol, and trichlorophenol, with several amphipathic poly (n-alkylmethyldiallylammonium) chlorides in aqueous solution was studied by ultrafiltration. The n-alkyl residues were octyl, decyl, and dodecyl and the binding degrees were significantly higher than those found with the hydrophilic poly (diallyldimethylammonium) chloride. The results agreed well with the Satake and Yang's treatment and Hill's empirical equation for the association process, thereby revealing, in both cases, an increasing cooperative effect as the polyelectrolyte side chain increased in length for the same phenol, and when the hydrophobic nature of the phenol increased for the same kind of polyelectrolyte. From the phenomenological association constants, the estimated molar standard free energies of association ranged from -19kJmol(-1), for the more hydrophilic phenoxide-polyelectrolyte pair, to -28kJmol(-1) for the more hydrophobic pairs. The main result is that the amphipathic nature of these polyelectrolytes makes them efficient systems to trap anionic contaminants, better than hydrophilic flocculants.},
keywords = {amphipathic aqueous-solution, association, binding, cooperative decyl, liquid-chromatography, micelles, partition-coefficients, phenols, polyelectrolytes, salts solubilization, sulfonates},
pubstate = {published},
tppubtype = {article}
}

@article{RN150,
title = {Cooperative Association of P-Alkylbenzene Sulfonates Sodium Salts to Poly-2-(Dimethylamino) Ethylmethacrylate-N-Alkyl Quaternized at the Water/Chloroform Interface},
author = { H. Rios and X. Briones and M. Urz\'{u}a and V. Vargas},
url = {/brokenurl#<Go to ISI>://WOS:000313621900008},
doi = {10.1080/00222348.2012.716334},
issn = {0022-2348},
year = {2013},
date = {2013-01-01},
journal = {Journal of Macromolecular Science Part B-Physics},
volume = {52},
number = {4},
pages = {614-622},
abstract = {The association of p-alkyl benzene sulfonate sodium salts with several poly-2-(dimethylamino) ethylmethacrylate-N-alkyl quaternized bromides at the water/chloroform interface was studied. High association percentages were found which increase with both the size of the sulfonate molecule and the length of the polyelectrolyte side chain: octyl, decyl, dodecyl and tetradecyl. The results fit well to the Hill's equation for the association of anionic surfactant to polyelectrolytes. Benzene sulfonate shows an anticooperative behavior for the association, whereas 4-methyl benzene sulfonate and 4-ethylbenzene sulfonate are increasingly cooperative for the association. From the association constants, the standard free energies of transfer from water to the interfacial polyelectrolytes were determined. Their values were a linear function of the number of carbon atoms of the aliphatic residue of the benzene sulfonate molecule ranging from -15.7 kJ/mol of CH2 groups for the octyl polyelectrolyte to -18.9 kJ/mol of CH2 groups for the tetradecyl derivative. These values are similar to those reported for the association of some of these sulfonates molecules with ammonium type cationic micelles. The results for the incremental free energy of transfer by mol of methylene group from water to micelles are in the same order of magnitude as those reported for p-alkyl phenoxides and p-alkylbenzoates to hexadecyltrimethyl ammonium bromide micelles. The results shows that amphipathic counterions as small as 4-ethylbenzenesulfonate are enough to induce a cooperative effect in their association to cationic polyelectrolytes.},
keywords = {aqueous-solution, association, binding, chloride chloroform-water cooperative counterions, dextran dodecyltrimethylammonium effects, hydrophobic interactions, interface, ions, micelles, polyelectrolyte polyelectrolytes, sulfate, sulfonate surfactant water},
pubstate = {published},
tppubtype = {article}
}