Electrokinetic and solvatochromic studies of functionalized silica particles

Spange, Stefan; Reuter, Anett; Prause, Silvio; Bellmann, Cornelia

doi:10.1163/156856100742672

Cited by 21 publications

(15 citation statements)

References 44 publications

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“…It can be assumed that the charge building process is governed by ion adsorption (preferentially anion adsorption) [19]. Results from other methods [21] corroborate the electrokinetic results. As demonstrated above, electrokinetic investigations may detect acid-base-properties at solid surfaces and thereby we obtain information about interaction mechanisms at the interface.…”

Section: Determining Factors For Dispersion Stabilitysupporting

confidence: 68%

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Stability of Dispersions

Bellmann¹

2004

Chem Eng & Technol

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The importance of the production and application of disperse systems in industry is steadily growing, while colloidal systems surround us every day (for example foodstuffs, pharmaceuticals etc.). Understanding the forces and mechanisms of interaction allows the development of new materials and improvement of available systems. The stability of such systems is one of the central research points. One of the well-known physical models of colloid stability is given by DLVO-Theory. With this theory we have a tool to influence the stability of such dispersion systems. In this paper, electrokinetic methods are used to investigate interaction forces in disperse systems. The influence of pH-value, electrolyte concentration and valency is shown with suitable examples. However, in some cases the DLVO-model is not satisfactory, and reasons for this behavior will also be discussed.

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Section: Determining Factors For Dispersion Stabilitysupporting

confidence: 68%

“…5) [21]. With the help of pH dependent zeta potential measurements, different surface active groups were detected corresponding to the chemical modification.…”

Section: Determining Factors For Dispersion Stabilitymentioning

confidence: 99%

Stability of Dispersions

Bellmann¹

2004

Chem Eng & Technol

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“…5) [21]. Mit Hilfe pH abhängiger Zetapotentialmessungen konnten die entsprechend der Modifizierung vorhandenen, oberflächenaktiven Gruppen detektiert werden.…”

Section: Methodenunclassified

“…In diesem Fall wird der Ladungsbildungsprozess an der Oberfläche durch Ionenadsorption (bevorzugt Anionenadsorption) bestimmt [19]. Ein Vergleich mit anderen Methoden [21] zeigt die Gültigkeit dieser Ergebnisse.…”

Section: Methodenunclassified

Stabilität von Dispersionen

Bellmann¹

2003

Chemie Ingenieur Technik

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Herstellung und Einsatz disperser Systeme gewinnen in der Industrie immer größere Bedeutung. Auch im täglichen Leben begegnen wir häufig solchen Systemen (z. B. Nahrungsmittel, Pharmazeutika usw.). Die Erforschung der Gesetzmäßigkeiten der Kolloidchemie ermöglicht, neue Stoffe zu entwickeln oder vorhandene zu verbessern. Ein zentraler Ansatzpunkt hierbei ist die Stabilität solcher kolloidalen Systeme. Eines der physikalischen Modelle zur Kolloidstabiltät liefert die DLVO‐Theorie. Entsprechend den physikalischen Bedingungen einer solchen Stabilisierungsform kann diese in vielfältiger Weise beeinflusst werden. Die hier vorzustellenden Arbeiten befassen sich mit dem Einsatz elektrokinetischer Messmethoden zur Untersuchung der Wechselwirkungskräfte in dispersen Systemen. An Beispielen soll der Einfluss von pH‐Wert, Elektrolytkonzentration und ‐wertigkeit auf die Kolloidstabilität gezeigt werden. Nicht immer erfüllen die untersuchten Dispersionen die Bedingungen des DLVO‐Modells. Ursachen für dieses Verhalten sollen diskutiert werden.

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“…Therefore, 4-aminobenzophenone (4)was used as indicator for measuring the b value, because the copper complex [Cu(tmen)(acac) + B(C 6 H 5 ) 4 -] [28,29] and an aminobenzofuranderivative, [19,32] which were previously used for this purpose, do not adsorb well to native cellulose samples.…”

Section: Probe Dye Indicators and Determination Of The Polarity Parammentioning

confidence: 99%

Empirical surface polarity parameters for native polysaccharides

Fischer

Spange²

2000

Macromol. Chem. Phys.

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The empirical Kamlet‐Taft solvatochromic polarity parameters α, β, and π* as well as calculated Reichardt's ET(30) values are presented for microcristalline cellulose, cellobiose, chitine, amylose, amylopectine, and glycogene. For this purpose, the following solvatochromic polarity indicators were applied: 2,6‐diphenyl‐4‐(2,4,6‐triphenyl‐1‐pyridinio)phenolate (1), [4,4′‐bis(N,N‐dimethylamino)benzophenone] (2), dicyano‐bis(1,10‐phenanthroline) iron(II) [Fe(phen)2](CN)2 (3), and 4‐aminobenzophenone (4). The polarity of the microcristalline environment of cellulose can be exactly parameterized in terms of the Kamlet‐Taft α, β, and π* values. The analogy of these values to those of the model compound cellobiose and of other independent literature data, i.e. calculated π* values via LSE (Linear Solvation Energy) relationships derived from FTIR and fluorescence measurements, is excellent. Microcristalline cellulose exhibit strong HBD properties and a rather low value of the dipolarity/polarizability. The substitution of the hydroxy group in the 2 position of the anhydroglucose unit of cellulose with the polarizable acetamido group (cellulose → chitine) significantly enhances the dipolarity/polarizability of the polysaccharide whereas the HBD capacity accordingly decreases. A generalized empirical polarity scale for native polysaccharides is suggested.

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Electrokinetic and solvatochromic studies of functionalized silica particles

Cited by 21 publications

References 44 publications

Stability of Dispersions

Stability of Dispersions

Stabilität von Dispersionen

Empirical surface polarity parameters for native polysaccharides

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