Counterion binding of poly(allylamine) hydrochloride in aqueous alcohols

2004

Polymer International

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Poly(allylamine) (PAlAm) gel was prepared by γ‐ray irradiation. Swelling behavior of the charged PAlAm gels having Cl− and NO3− counter‐ions (PAlAmHCl and PAlAmHNO3, respectively) was investigated in aqueous organic solvent mixtures as functions of solvent species (dimethylsulfoxide (DMSO), methanol (MeOH), ethanol (EtOH), 2‐propanol (2PrOH), tert‐butanol (tert‐BuOH), acetone, tetrahydrofuran (THF) and dioxane) and the concentration. With increasing solvent concentration, the gels (except for the DMSO system) showed a sharp deswelling comparable to the volume phase transition. The solvent specificity for the PAlAmHNO3 gel transition was correlated with the dielectric constant of the organic solvents, while that for the PAlAmHCl gel suggested that solvency for the counter anion is another important factor. Copyright © 2004 Society of Chemical Industry

Section: Resultsmentioning

confidence: 82%

Solvent‐specific swelling behavior of poly(allylamine) gel

Yasumoto

Hata

2004

Polymer International

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“…Counterion binding of polyelectrolytes is an essential factor for ordered structures of biopolymers such as DNA,1 proteins,2 and charged polysaccharides3 and their functions in vivo as well as for the volume phase transition of synthetic polymer gels4, 5 in vitro. We have been studying counterion binding of some synthetic6, 7 and biopolyelectrolytes8–10 in water/organic solvent mixtures and found marked ion‐ and solvent‐specificities for binding and the resultant structure transition, such as gel collapse11–13 due to ion‐cluster formation and the coil–helix transition of charged polypeptides. For example, α ‐helix conformation of sodium poly(L‐glutamate) (PLGNa) was stabilized in aqueous solutions containing an organic solvent in a higher ratio, for example, ≧ 70 vol % ethanol, while the stability was significantly reduced for the potassium salt or in aqueous t ‐butanol 8.…”

Section: Introductionmentioning

confidence: 99%

Counterion binding in Na poly(acrylate) gel. An ²³Na‐NMR study

Minato

J Polym Sci B Polym Phys

2004

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Counterion binding in Na poly(acrylate) gel immersed in water/organic solvent [ethanol (EtOH), acetonitrile (AcN), or tetrahydrofuran (THF)] mixtures was investigated by 23Na‐NMR spectroscopy. With an increase in the content of an organic solvent (∼40–50 vol %), the 23Na chemical shift significantly moved downfield on a gel collapse. This downfield shift strongly suggests that the gel collapse was induced by contact ion‐pair formation between the counterion and the carboxyl anion on the polymer. With a further increase in the solvent content (∼90 vol %), the chemical shift for an EtOH system showed a slight upfield shift, while THF and AcN systems maintained downfield shifts. The contrasting behaviors for EtOH and the latter two solvent systems were interpreted as being caused by desolvation and resolvation of bound Na+ counterions because of deswelling and reswelling of the respective gels in the pertinent solvent concentration regions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4412–4420, 2004

“…Another, more direct investigation on counterion binding in mixed solvents was performed with poly(allylamine)hydrochloride. Miura et al 12 measured an apparent counterion activity, aЈ, in aqueous MeOH, EtOH, and 2PrOH and found that the experimental aЈ values deviated downward from a prediction by a counterion condensation theory when the alcohol content was increased. The deviation was interpreted as caused by specific counterion binding or contact ion-pair formation.…”

Section: Introductionmentioning

confidence: 99%

“…When less polar solvents are added into water, significant desolvation may occur upon the counterion binding, the strength of which would be determined by the solvating ability of the relevant solvent to the polymer charge and the counterion, as well as by D. "Solvent effects" on the counterion binding have been studied mainly in solution systems. 11,12 Satoh et al 13 investigated salt-and solvent-induced helix formation of poly(L-glutamic acid) (PLG) in aqueous alcohols and observed the following counterion and solvent specificity in the helix stabilization: Cs ϩ Ͻ K ϩ Ͻ Li ϩ Ͻ Na ϩ and tBuOH Ͻ 2PrOH Ͻ EtOH. These orders were interpreted as those for the stability of contact ion pairs formed between the polymer charge (OCOO Ϫ ) and alkali metal cations in the relevant solvent systems: PLG can assume an ␣ helix even in the fully charged state if the charges are effectively neutralized with the contact ionpair formation.…”

Section: Introductionmentioning

confidence: 99%

Solvent‐ and counterion‐specific swelling behavior of poly(acrylic acid) gels

Nishiyama

J. Polym. Sci. B Polym. Phys.

2000

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The collapse of alkali metal poly(acrylate) (PAAM) gels was investigated for various water/organic solvent mixture systems: methanol (MeOH), ethanol (EtOH), 2-propanol (2PrOH), t-butanol (tBuOH), dimethyl sulfoxide (DMSO), acetonitrile (AcN), acetone, tetrahydrofuran (THF), and dioxane. In order to ascertain the counterion specificity in the swelling behavior, four kinds of alkali metal counterions were used: Li ϩ , Na ϩ , K ϩ , and Cs ϩ . Remarkable solvent and counterion specificities were observed for every counterion species and every solvent system, respectively. For example, in aqueous EtOH the dielectric constants (D cr ) at which collapse occurred were in the order PAACs Ͻ PAALi Ͻ PAAK Ͻ PAANa. On the other hand, the D cr at which PAALi gel collapsed increased in the order tBuOH Ͻ dioxane Ͻ THF Ͻ MeOH Ͻ 2PrOH Ͻ EtOH Ͻ acetone Ͻ AcN Ͻ DMSO, where the D cr ranged from about 39 to about 67. This was in contrast to our previous observation for a partially quaternized poly(4-vinyl pyridine) (P4VP) gel, which collapsed in a much narrower D cr region in similar mixed solvents. The present solvent-and counterion-specific collapses are discussed on the basis of solvent properties such as the dielectric constant and Gutmann's donor number and acceptor number of a pure solvent.