Colligative properties of polyelectrolyte solutions. IV. Activity coefficient of sodium ion

Nagasawa, Mitsuru; Kagawa, Ikumi

doi:10.1002/pol.1957.1202510806

Cited by 75 publications

(32 citation statements)

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“…In order to raise the precipitation threshold, the polymer dissolved in the solution should be dissociated to decrease the local activity product of dissolved ions. 1,4 Sillafin-1 is basic and a short chain length polymer. 9 So it can be dissociated at weakly acidic pH value and therefore will be a candidate of ionic polymer which raise precipitation threshold of the salt solution in silica biomineralization.…”

Section: Discussionmentioning

confidence: 99%

“…The PAA in the outer solution also serves as an analogue of osteopontin, osteocalcin 3 and other acidic proteins which like PAA, bear acidic groups that are dissociated at pH ¼ 7:4. Since this dissociation decreases the local activity product of dissolved ions by an electrostatic effect, 4 PAA, osteopontin, osteocalcin and other acidic proteins can raise source ion concentrations of precipitation threshold in the outer solution. The similarities between collagen and PVA and also between bone sialoprotein and PAA imply that like PVA and PAA, collagen and bone sialoprotein can be expected to experience attractive forces due to hydrogen bonding and to form a polymer complex that is transformed into a hydrogel in aqueous solution.…”

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confidence: 99%

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Hypercomplex Gel Changes to Organic/Inorganic Solid Solution by Phase Transition in an Artificial Biomineralization System

Iwatsubo

Yamaguchi

2008

Polym J

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In an artificial biomineralization system, a polymer complex consisting of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) was utilized as a mineralization field. The polymer complex was immersed in salt solution containing x mM CaCl 2 , 0:6x mM KH 2 PO 4 , and PAA at pH ¼ 7:4. After equilibrium was reached, the weight uptake in the polymer complex was determined in the dry state. When x was less than the transition concentration (x T ), the polymer complex was transformed into a hydrogel, and the dry weight uptake gradually increased with increasing x. On the other hand, at x greater than x T , the polymer complex was transformed into an organic/inorganic solid composite, and the dry weight uptake was almost independent of x. The hydrogel formed was a hypercomplex gel composed of Ca 2þ and HPO 4 2À ions and the polymer complex held together by hydrogen bonds and electrostatic interactions. The organic/inorganic solid composite appeared to be a solid solution of the polymer complex and hydroxyapatite, as indicated by experiments on the saturation state of the salt solutions. Our results indicate that the hypercomplex gel changed discontinuously to the organic/inorganic solid solution at x ¼ x T ; this discontinuity represents a phase transition of hypercomplex gel to organic/inorganic solid solution that is an open system whose border is permeable to both energy and mass. The hypercomplex gel and the organic/inorganic solid solution can serve as models for the fundamental structures of cartilaginous and skeletal material respectively.KEY WORDS: Biomineralization / Hypercomplex Gel / Organic/inorganic Solid Solution / Miscibility / Phase Transition / Catilaginous Material / Skeletal Material / Skeletal materials (endoskeleton and exoskeleton) formed by biomineralization are not pure Ca 5 (PO 4 ) 3 (OH), CaCO 3 , or SiO 2 but composites of organic polymers and the respective minerals. The polymers play a principal role in biomineralization and are believed to endow skeletal materials with resistance to fractures by overcoming the fragility inherent in the mineral component. Biomineralization is controlled by both species-specific genetic information and physicochemical parameters. Once the necessary solute ions and organic polymers have been produced and assembled by the organism, the subsequent stages of biomineralization are controlled primarily by physicochemical factors such as pH and the concentrations of the polymers and ions, which affect interactions between them in aqueous solution. Although the physicochemical mechanism of biomineralization has been investigated for many years, the mechanism is still unknown, even for cases in which the monomer sequence of the polymers is clarified.In previous work, we discovered the physicochemical regularity in the polymer systems related to hydroxyapatite (HAP), CaCO 3 and SiO 2 skeletal materials, and an artificial biomineralization system has been constructed using a polymer complex hydrogel composed of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) t...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Hypercomplex Gel Changes to Organic/Inorganic Solid Solution by Phase Transition in an Artificial Biomineralization System

Iwatsubo

Yamaguchi

2008

Polym J

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“…A series of sodium salts of the mixtures of linear polyphosphates were obtained by a solubility fractionation with acetone or gel chromatographic fractionation of Graham's salt [1,2] where the liquid junction potential between the Na + ion solution and a saturated KCl solution is assumed constant for different concentrations of sample solutions [3]. The activities of Na+ ion in NaCl solutions, which have been used for the standardization of the electrodes, were calculated by use of the activity coefficients of Na+ ion reported by Kielland [4].…”

Section: Experimental Chemicalsmentioning

confidence: 99%

Counterion Binding to Inorganic Polyphosphate Anions (I)

Miyajima

Kakehashi

1993

Phosphorus Research Bulletin

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The change in the Na+ ion binding properties of a series of the anions of inorganic phosphates (phosphinate, cyclic polyphosphate, and linear polyphosphate) has been studied in order to see the transition from simple electrolyte to polyelectrolyte. Na+ ion activity measurement together with 23 Na NMR peak width measurement gave a consistent conclusion that about 100 of the chain-length is needed to show the binding properties independent of the chain-length in salt-free system.

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“…The counterion binding to poly- ion depends on its charge density. 12 At a=0, P AAH + is a fully charged vinylic polyelectrolyte forming a high electrostatic field around it. Therefore, the added EBS -'s are accumulated around the P AAH + moieties.…”

Section: Binding Of Ebs-'s By P Aah+ and Theirmentioning

confidence: 99%

Binding of Hydrophobic Counterions by Polyelectrolyte and Their Hydrophobic Association around Polyion

Itaya

Ueda

Ochiai

et al. 1993

Polym J

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ABSTRACT:The binding of p-ethylbenzenesulfonate ions (EBS-'s) by poly(allylammonium) cation (PAAH+) and their hydrophobic association around PAAH+ have been investigated in aqueous solutions through 1 H NMR and c1-activity measurements. At a constant PAAH+c1-concentration, all 1 H NMR signals of EBS-exhibited up-field shift (ring current shift) with the increase in the NaEBS concentration. However, any chemical shift change did not observe in each signal of PAAH+. These results show that EBS-'s atmospherically bound to PAAH+ associate each other due to their hydrophobic interaction. The association of EBS-'s is depressed by the decrease in the charge density of the polyion and broken by the addition of another simple salt (NaCl) to the PAAH+c1-;NaEBS system. Moreover, it was found that the counterion exchange from CJ-'s to EBS-'s around PAAH+ is efficiently promoted by the association of EBS-'s.KEY WORDS Poly(allylammonium) Cation / Hydrophobic Counterion / Atmospherical Binding / Association of Hydrophobic Counterions / Counterion Exchange / The properties of polyelectrolyte solutions depend, very much, on the electrostatic interactions between charges fixed along the polymer backbone. These interactions are also very sensitive to the presence of counterions. The addition of electrolyte to the medium screens out the repulsive interactions between charges through the counterion binding and/or condensation around the polyion with a high electrostatic potential. This counterion binding (condensation) is an important feature of polyelectrolyte solutions. 1 Thus, the solution properties are considerably modified accompanying the changes in the chain conformation, water structure, degree of hydration around the polyion, and so on. On the one hand, when hydrophobic salt is used as an added electrolyte, z-4 the hydrophobic counterion, which has both hydrophilic and hydrophobic moieties, may have a different influence upon these electrostatic interactions. Especially, interactions among hydrophobic counterions should be also taken into account when polyion/hydrophobic counterion system is examined, although this interaction would be negligible in the absence of polyion. 5 In the previous work, 6 the interaction of three hydrophobic ions, i.e., benzenesulfonate (BS-), p-methylbenzenesulfonate (MBS-), pethylbenzenesulfonate (EBS-) with PAAH+ cation was investigated by 1 H NMR and viscosity measurements. It was found that EBS -'s accumulated electrostatically around the polyion can associate each other through their hydrophobic interaction. But, BS -and MBS-, which are slightly less hydrophobic than EBS -, did not show any sign of such hydrophobic association. This indicates that the hydrophobicity of counterion plays an important role in the association of counterions 545

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Colligative properties of polyelectrolyte solutions. IV. Activity coefficient of sodium ion

Cited by 75 publications

References 16 publications

Hypercomplex Gel Changes to Organic/Inorganic Solid Solution by Phase Transition in an Artificial Biomineralization System

Hypercomplex Gel Changes to Organic/Inorganic Solid Solution by Phase Transition in an Artificial Biomineralization System

Counterion Binding to Inorganic Polyphosphate Anions (I)

Binding of Hydrophobic Counterions by Polyelectrolyte and Their Hydrophobic Association around Polyion

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