Characterization of gelatin-surfactant interaction by thickness measurements of foam films

Wüstneck, R.; Müller, Hans‐Joachim

doi:10.1007/bf01410312

Cited by 25 publications

(5 citation statements)

References 18 publications

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“…Above its IEP, a substantial increase in viscosity was observed . Clear evidence of the adsorption of micellar aggregates on G at [SDS] ≪ cmc (critical micellar concentration) has been reported from different laboratories. – Complex formation with negatively charged G and polyanions like sodium polystyrenesulfonate (NaPSS) or sodium poly(2-acrylamido-2-methylpropanesulfonate) was effective by polarization-induced attraction, as revealed from light scattering studies . Interaction of mixed micelles of SDS and a sugar-based nonionic surfactant with G depended both on a critical mole fraction of SDS as well as on the alkyl chain length of the nonionic surfactant .…”

Section: Introductionmentioning

confidence: 92%

Physicochemical Studies on the Interaction of Gelatin with Cationic Surfactants Alkyltrimethylammonium Bromides (ATABs) with Special Focus on the Behavior of the Hexadecyl Homologue

2008

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The interaction of a denatured interfacially active protein, gelatin (G) (at pH 9, above its isoelectric pH 4.84, and ionic strength mu=0.005), with a cationic amphiphile, hexadecyl (or cetyl) trimethylammonium bromide, CTAB, has been elaborately studied using a variety of techniques. Two types of protein-surfactant complexes at a concentration below the normal critical micellar concentration (cmc) were formed in solution. The first, G-CTAB (monomer) combined complex (GS(n)(I)) adsorbed at the air/solution interface, followed by its gradual transformation to the poor interfacially active second G-CTAB (aggregate) complex (GS(m)(B)) at a critical aggregation concentration (cac) of the interacting oppositely charged surfactant. In the higher concentration range, upon completion of GS(m)(B) formation, coacervation (association of GS(m)(B)) led to add turbidity. With increasing addition of CTAB, the coacervates became disintegrated and ultimately remained dissolved in the free micellar solution of CTAB. The above features were studied using the techniques of tensiometry, conductometry, turbidimetry, fluorimetry, and microcalorimetry. The interaction features were prominent at [G] >or= 0.05 g %, and several of these were either marginal or absent at [G]<0.05 g %. The denatured protein was found to form viscous as well as gel-forming consistencies at higher [G] and at lower temperature. A temperature variation study on the interaction of G with CTAB has revealed that enhanced interaction takes place at higher temperature. The effect of [G] on its interaction with cationic surfactants of varying chain length in the alkyltrimethylammonium bromide (ATAB) series has been also studied; a similar interactional profile as that of CTAB has been exhibited by octadecyltrimethylammonium bromide; however, the lower homologues (dodecyl- and tetradecyl-) of ATAB have offered different profiles. It has been found that the ATABs with higher alkyl chain lengths were more interactive with negatively charged G than their lower homologues. Quantification of the results in terms of different transition points, counterion binding of the protein-bound surfactant aggregates and free micelles, the enthalpy of binding interactions and energetics of ATAB micellization, and so forth have been studied. The results have been rationalized in terms of an interaction model.

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Section: Introductionmentioning

confidence: 92%

Physicochemical Studies on the Interaction of Gelatin with Cationic Surfactants Alkyltrimethylammonium Bromides (ATABs) with Special Focus on the Behavior of the Hexadecyl Homologue

2008

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“…Gelatin and anionic surfactants exhibit much of the character of the these interactions. − Early studies were concerned with the formation of precipitates below the isoelectric point (IEP) 25 and substantial increases in the viscosity above the IEP. Studies using surface tension, , equilibrium dialysis, , ion-selective electrode response, ,,− and film thickness 38 suggest that gelatin nucleates the formation of adsorbed, anionic micelles at a substantially lower concentration than the critical micelle concentration (cmc). At a pH higher than the IEP, as sodium dodecyl sulfate (SDS) binds to gelatin, the pH increases as carboxylate groups protonate so as to reduce the net negative charge of the complex.…”

Section: Introductionmentioning

confidence: 99%

Interaction between a Partially Fluorinated Alkyl Sulfate and Gelatin in Aqueous Solution

et al. 2004

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The interaction of a partially fluorinated alkyl sulfate, sodium 1H,1H,2H,2H-perfluorooctyl sulfate (C6F13CH2CH2OSO3Na), with the polyampholyte gelatin has been examined in aqueous solution using surface tension and small-angle neutron scattering (SANS). The 19F chemical shift of each fluorine environment in the surfactant is unaltered by the addition of gelatin, indicating that there is no contact between the gelatin and the fluorocarbon core of the micelle. The chemical shift of the two methylene groups closest to the headgroup is altered when gelatin is present, disclosing the location of the polymer. The critical micelle concentration (cmc) of the surfactant, cmc = 17+/-1 mM, corresponds to an effective alkyl chain (CnH2n+1) length of n = 11. In the presence of gelatin, the cmc is substantially reduced as expected, cmc(1) = 4+/-1 mM, which is also consistent with an effective alkyl chain length of n = 11. In the presence of the fluorosurfactant, the monotonic decay of the SANS from the gelatin-only system is replaced by a substantial peak at an intermediate Q value mirroring the micellar interaction. At low ionic strengths, the gelatin/micelle complex can be described by an ellipsoid. At higher ionic strengths, the electrostatic interaction between the micelles is screened and the peak in the gelatin scattering disappears. The correlation length describing the network structure decreases with increasing SDS concentration as the bound micelles promote a collapse of the network.

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“…The formation of gelatin−surfactant complexes is particularly relevant in the latter application since surfactants are commonly incorporated into gelatin containing solutions to promote emulsification and to control surface tension during coating operations. The formation of complexes of gelatin and anionic surfactants has been studied by precipitate formation below the isoelectric point, , rheology, , surface tension, − equilibrium dialysis, , ion-selective electrode studies, film thickness, and 13 C NMR spectroscopy …”

Section: Introductionmentioning

confidence: 99%

Interaction between Gelatin and Anionic Surfactants

et al. 1996

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The effects of alkyl chain length of homologous alkyl sulfate surfactants ranging from C8 to C14 on the diffusion behavior of both the surfactant and gelatin have been investigated by pulsed-gradient spin-echo NMR spectroscopy. Changes in the diffusivity of the surfactant can be rationalized in terms of a two-state model consisting of gelatin-bound micelles in equilibrium with freely diffusing unimeric surfactant. A minimum in the diffusivity of gelatin is observed when the binding of surfactant amounts to about 1 micelle/strand. The depth of this minimum increases with the chain length of the surfactant. These effects are explained in terms of micelle-mediated transient cross-links as proposed by Greener et al. (Macromolecules 1987, 20, 2490). The effective strength of the cross-links is a decreasing function of the number of micelles/strand because of the electrostatic repulsion between the micelles; the strength increases with an increase in the size of the micelles.

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Characterization of gelatin-surfactant interaction by thickness measurements of foam films

Cited by 25 publications

References 18 publications

Physicochemical Studies on the Interaction of Gelatin with Cationic Surfactants Alkyltrimethylammonium Bromides (ATABs) with Special Focus on the Behavior of the Hexadecyl Homologue

Physicochemical Studies on the Interaction of Gelatin with Cationic Surfactants Alkyltrimethylammonium Bromides (ATABs) with Special Focus on the Behavior of the Hexadecyl Homologue

Interaction between a Partially Fluorinated Alkyl Sulfate and Gelatin in Aqueous Solution

Interaction between Gelatin and Anionic Surfactants

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