Symposia. Symposium on the Rheology of Concentrated Dispersions: Preface

Marlow, Bruce J.; Zukoski, Charles F.

doi:10.1021/la00091a601

Cited by 7 publications

(3 citation statements)

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“…A study into the effect on μ eo of ionic strength and σ surf (electrophoretic fingerprinting) would shed light on which other mechanisms chiefly limit the effective surface charge. Preliminary measurements in this direction have been made.…”

Section: Resultsmentioning

confidence: 99%

Capillaries Modified by Polyelectrolyte Multilayers for Electrophoretic Separations

1999

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Fused silica capillaries coated with thin films of physically adsorbed charged polymers are employed for capillary zone electrophoretic separations. The coating is a polyelectrolyte multilayer, constructed in situ by alternating rinses with positively and negatively charged polymers. The thickness of the multilayer and amount of surface charge is controlled by the concentration of salt in the deposition solutions. The direction of the electroosmotic flow oscillates as the multilayer surface charge alternates in polarity during buildup. The apparent surface charge, deduced from the electroosmotic mobility, is considerably less than the nominal surface charge of the film. Mechanisms limiting this apparent surface charge for a bufferpermeable layer are discussed. The multilayer-coated columns exhibit many desirable features in addition to ease of construction and reproducible control of electroosmotic flow: stable flow rates are achieved immediately on exposure of the column to running buffer, and reversed flow is possible. Columns are also found to be stable to extremes of pH and ionic strength, and to dehydration/rehydration. A series of basic proteins are separated with good efficiency, demonstrating column resistance to irreversible protein adsorption. Partitioning and separation of neutral solutes using thicker films is demonstrated.

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Section: Resultsmentioning

confidence: 99%

Capillaries Modified by Polyelectrolyte Multilayers for Electrophoretic Separations

1999

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“…It is not sufficient to measure the mobility as a function of pH alone because deeper regions of the charged layer structures contribute to the electrophoretic mobility only at sufficiently low ionic strength where the Debye length is comparable with or larger than the thickness of the polyelectrolyte layer. The systematic measurement of the mobility as a function of both the pH and ionic strength (conductivity), called electrophoretic fingerprinting, has been used below to explore the electrostatic properties of poly(styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) deposited on poly(styrene sulfate) latex particles. In contrast to biological surfaces these synthetic polyelectrolytes are highly charged.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Hairy Layer Theory of Electrophoretic Fingerprinting Applied to Consecutive Layer by Layer Polyelectrolyte Adsorption onto Charged Polystyrene Latex Particles

et al. 1997

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The consecutive layer-by-layer adsorption of poly(allylamine hydrochloride) (PAH) and poly(styrenesulfonate) (PSS) on colloidal charged latex particles is investigated by measuring the electrophoretic mobility as a function of pH and ionic strength over a broad range (electrophoretic fingerprinting). Meaningful interpretation of the data required the development of a nonlinear approach to hairy particle electrophoresis including dissociation, adsorption, and association. Steric and electrostatic exclusion of mobile ions from the hairy layer has been considered. Also, the surface conductivity correction is extended to the case of charged hairy layer particles. We deposited up to three polyelectrolyte layers. The following were found: (i) Each layer deposition is accompanied by charge overcompensation and (ii) Not only the top layer but also the underneath layers and the naked latex particle surface contribute to the particle mobility. This can be interpreted as an incomplete coverage or a polyelectrolyte interpenetration. (iii) The thickness of the top adsorbed hairy layer is of the order of 1 nm. (iv) About one-third of the charged groups of the top layer form ion pairs with the underneath charges. (v) Counterion adsorption to the charged groups of the top layer can be observed.

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“…Consequently, a combined variation of ionic strength and pH is thus necessary for a comprehensive electrophoretic investigation. To underline the significance of the resulting three-dimensional graph for the characterization of the surface structure, this method has been called “electrophoretic fingerprinting”. , …”

Section: Introductionmentioning

confidence: 99%

“Hairy Surface Layer” Concept of Electrophoresis Combined with Local Fixed Surface Charge Density Isotherms: Application to Human Erythrocyte Electrophoretic Fingerprinting

et al. 1996

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In order to describe the electrophoretic behavior of “hairy-layer”-coated particles, local charge density isotherms have been combined with considerations of hydrodynamic flow penetration into the layer. An iterative numerical procedure was employed to calculate the electrophoretic mobility as a function of both pH and salt concentration. A major result is that information can be gained regarding the distribution functions of oppositely charged groups from the behavior of the point of zero mobility as a function of pH and salt concentration. The theoretical results were used to reinterprete the electrophoretic behavior of native, neuraminidase-treated and glutaraldehyde-treated human erythrocytes. Theoretical analysis of the experimental data revealed that negative groups had occurred preferentially in the outer regions of the layer. A penetration depth of 1 nm into the 3.5 nm thick hairy layer successfully accounted for the erythrocyte mobility data for all methods of analysis tried. Upon sialic acid removal, alterations of the glycocalyx structure occurred, resulting in possible changes in the fixed charge distribution. It was concluded that intramolecular, as well as intermolecular, electrostatic interactions are important for the structure of the hairy surface layer (glycocalyx). No evidence for the adsorption of small ions was found.

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Symposia. Symposium on the Rheology of Concentrated Dispersions: Preface

Cited by 7 publications

References 0 publications

Capillaries Modified by Polyelectrolyte Multilayers for Electrophoretic Separations

Capillaries Modified by Polyelectrolyte Multilayers for Electrophoretic Separations

Nonlinear Hairy Layer Theory of Electrophoretic Fingerprinting Applied to Consecutive Layer by Layer Polyelectrolyte Adsorption onto Charged Polystyrene Latex Particles

“Hairy Surface Layer” Concept of Electrophoresis Combined with Local Fixed Surface Charge Density Isotherms: Application to Human Erythrocyte Electrophoretic Fingerprinting

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