Ionic Strength Effects in Aqueous Solutions of Gelatin and Sodium Dodecylsulphate

Griffiths, Peter Charles; Roe, J. A.; Abbott, R. J.; Howe, Andrew M.

doi:10.1080/13682199.1997.11736413

Cited by 14 publications

(13 citation statements)

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“…Irrespective of the presence, number, and size of the grafted hydrophobe CMC(2) = 10 (±1) mM. At CMC(2) there must be a CMCs worth of SDS unimer, which corresponds to about 7.5 mM bound surfactant or about three or four micelles per gelatin molecule, based on an aggregation number of 50 (±5) . This is in good agreement with other published estimates of the micelle occupancy …”

Section: Resultssupporting

confidence: 87%

“…The parameters describing the morphology of the bound SDS micelle under these conditions of pH and ionic strength are the same as those describing a nonadsorbed SDS micelle under the same conditions, in agreement with the SANS results of Cosgrove et al . , and the fluorescence data of Whitesides and Miller 6 and Griffiths et al…”

Section: Resultsmentioning

confidence: 93%

“…Increasing the ionic strength or adding a surfactant such as sodium dodecyl sulfate (SDS) perturbs the balance of these various interactions, and accordingly, the conformation of the gelatin molecule is altered. Our previous work − concerned the interaction of gelatin with surfactants using a range of techniques. The structure of the gelatin/SDS complex above its isoelectric point is thought to involve some hydrophobic gelatin residues in the core of the micelle, positively charged residues associated with the surfactant palisade layer, and the negatively charged and hydrophilic-uncharged residues repelled from the micellar surface, forming loops out into solution.…”

Section: Introductionmentioning

confidence: 99%

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Hydrophobically Modified Gelatin and Its Interaction in Aqueous Solution with Sodium Dodecyl Sulfate

et al. 2001

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The interaction between a series of hydrophobically modified gelatins and the anionic surfactant sodium dodecyl sulfate SDS in a pH ) 6.6/34 mM buffer has been investigated by surface tension, pulsed-gradient spin-echo NMR, viscosity, and small-angle neutron scattering. In the absence of the surfactant, the bulk viscosity of all the gelatins examined here is dependent only on the gelatin concentration and is independent of the number and size of any grafted hydrophobe. Similarly, the small-angle neutron scattering for all samples could be well-described by a two length-scale model. In this model, the smaller dimension represents the local structure of the gelatin molecule and is unaffected by the presence of the hydrophobe(s), while a larger dimension characterizing the network structure increases significantly with the presence of the hydrophobe but not their size. On addition of the anionic surfactant sodium dodecyl sulfate (SDS), the interaction between surfactant and the hydrophobic gelatin with low grafting densities starts at a slightly lower surfactant concentration (CMC(1)) compared with a "blank" material that has no grafted hydrophobe. At higher grafting densities, CMC(1) is greater than the CMC(1) values for the lower grafting density series. For both grafting densities, neither the length nor the number of hydrophobes present has an appreciable effect on CMC(1). There is no change in the amount of SDS bound to the gelatin at saturation. The viscosities of the hydrophobically modified gelatin/SDS solutions do depend on the length of the hydrophobe, albeit rather weakly, but only at the higher grafting density. In summary, the interaction between these gelatin samples and SDS is dominated by the electrostatics of the system; the effects of the hydrophobe are proposed to be largely manifestations of the change in the electrostatic character of the gelatin induced by grafting process, rather than the hydrophobe per se.

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Hydrophobically Modified Gelatin and Its Interaction in Aqueous Solution with Sodium Dodecyl Sulfate

et al. 2001

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“…Small-angle neutron scattering (SANS) studies on gelatin/sodium dodecyl sulfate (SDS) solutions suggest that these adsorbed micelles have a comparable size to nonadsorbed SDS micelles, although the SANS estimates are strongly model dependent. In contrast, fluorescence-quenching studies point to a slightly lower aggregation number than in the absence of the gelatin . At gelatin concentrations above the critical overlap concentration, C *, the onset of an association with SDS micelles is accompanied by an increase in solution viscosity as the anionic micelles provide transient bridges between gelatin molecules .…”

Section: Introductionmentioning

confidence: 85%

Micellization of Sodium Dodecyl Sulfate with a Series of Nonionic n-Alkyl Malono-bis-N-methylglucamides in the Presence and Absence of Gelatin

Griffiths¹,

Roe²,

Jenkins³

et al. 2000

Langmuir

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The critical micelle concentrations (cmc's) for binary mixtures of sodium dodecyl sulfate (SDS) and nonionic n-alkyl malono-bis-N-methylglucamides (C n BNMG) have been measured by surface tension. Synergistic interactions over the entire mole fraction range are observed when the nonionic alkyl chain length n is either 10 or 12. A switch from antagonistic behavior at low SDS solution mole fractions to synergistic behavior at high SDS solution mole fractions is observed for the C14BNMG/SDS mixture. The dodecyl sulfate unimer concentrations in binary mixtures of C12BNMG/SDS are well described by regular solution theory (Rubingh, D. N. Solution Chemistry of Surfactants; Plenum: New York, 1979), using the experimentally determined cmc values. On addition of gelatin, the cmc is depressed for the binary C10BNMG/SDS and C12BNMG/SDS combinations, but only above a critical SDS solution mole fraction, . Therefore, interaction between the gelatin and the mixed micelles is only seen above . No corresponding value is found for the C14BNMG/SDS system. Here, cmc's are unchanged by the presence of gelatin for any mixture, thus indicating no interaction between the mixed C14BNMG/SDS micelle and gelatin. On increasing the nonionic alkyl chain length from 10 to 12, increases. For the latter system where both components possess dodecyl tails, the dodecyl sulfate unimer concentration is reduced for solutions above but remains unchanged for solutions below , relative to the no-gelatin case. The composition of the bound micelle is very different from that formed in the absence of gelatin. Furthermore, whereas the compositions of the micelle and solution are vastly different in the absence of gelatin, they are very similar in the presence of gelatin. Not only does the nonionic surfactant promote binding of SDS to gelatin, but at the highest SDS mole fraction studied, it induces pre-cmc(1) nonmicellar SDS binding.

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“…To minimize the interactions of free groups on the side chains of gelatin with other molecules in the solution, a small amount of surfactant was added to the gelatin samples. Weakly charged polyampholytes such as gelatin form complexes with anionic surfactants, which stabilize the structure and free groups on the side chains of gelatin (Griffiths, Roe, Abbott, & Howet, 1997).…”

Section: Prion Detection In Gelatin Solutionsmentioning

confidence: 99%

A bio-sensing strategy for the detection of prions in foods

Anand

Moreira

Henry

et al. 2005

LWT - Food Science and Technology

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Ionic Strength Effects in Aqueous Solutions of Gelatin and Sodium Dodecylsulphate

Cited by 14 publications

References 0 publications

Hydrophobically Modified Gelatin and Its Interaction in Aqueous Solution with Sodium Dodecyl Sulfate

Hydrophobically Modified Gelatin and Its Interaction in Aqueous Solution with Sodium Dodecyl Sulfate

Micellization of Sodium Dodecyl Sulfate with a Series of Nonionic n-Alkyl Malono-bis-N-methylglucamides in the Presence and Absence of Gelatin

A bio-sensing strategy for the detection of prions in foods

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