Interaction forces between particles stabilized by a hydrophobically modified inulin surfactant

Nestor, Jérémie; Esquena, Jordi; Solans, Conxita; Luckham, P.F.; Musoke, Michael; Levecke, Bruno; Booten, Karl; Tadros, Tharwat F.

doi:10.1016/j.jcis.2007.03.011

Cited by 48 publications

(39 citation statements)

References 28 publications

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“…Above C el, cr the loops and tails became significantly collapsed, giving thinner layers and this could produce small foam bubbles. Evidence of the collapse of the tails and loops on addition of electrolyte has recently been obtained using Atomic Force Microscopy [ 4 ]. Figure 2A, B shows the foam lifetime τ p dependence on applied pressure ∆P at two different INUTEC SP1 concentrations of 2 × 10 −5 and 1 × 10 −4 mol.dm −3 .…”

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confidence: 82%

“…Previous investigation in our laboratory showed that this graft-copolymer produced highly stable oil-inwater emulsions particularly in the presence of high electrolyte concentrations [ 3 ]. This high stability could be attributed to the strong adsorption of the polymeric surfactant (with multi-point attachment with several alkyl groups and the strong hydration of the linear polyfructose loops and tails) [ 3,4 ]. More evidence of this high stability has recently been obtained by investigation of emulsion films containing the polymeric surfactant [ 5 ].…”

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confidence: 99%

“…The question why foam dispersity changes within electrolyte concentrations over 10 −1 mol.dm −3 is not clear yet. A probable explanation could be that the conformation of the loops and tails of polyfructose of the surfactant changes within this electrolyte concentration range [ 3,4 ]. This, however, deserves additional study and experimental corroboration.…”

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confidence: 99%

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Dotchi Exerowa. Foams Stabilized by Hydrophobically-modified Inulin Polymeric Surfactant

Христов¹,

Gotchew²,

Petkova³

et al. 2013

Proceeding BAS

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The foams and foam films stabilized by hydrophobically-modified inulin polymeric surfactant (INUTEC SP1) were investigated as a function of electrolyte concentrations. The Foam Pressure Drop Technique was applied to obtain the foam lifetime at constant capillary pressure. The Film Pressure Balance Technique was simultaneously applied to obtain the disjoining pressure as a function on film thickness. The results showed that at INUTEC SP1 concentration of 2 × 10 −5 mol.dm −3 and constant capillary pressure of 5 kPa the foam lifetime τ p was independent of electrolyte concentration in the range from 10 −4 to 10 −1 mol.dm −3 NaCl. Above 10 −1 mol.dm −3 NaCl, the foam lifetime increased rapidly with the increase in NaCl concentration and the most stable foams were produced from solutions containing 1 and 2 mol.dm −3 NaCl. The critical pressure P cr, foam above which foam collapse (avalanche-like) occurred increased with the increasing of electrolyte concentration and this explained the higher stability of the foam at high NaCl concentrations. The disjoining pressure (Π)-thickness (h) isotherms showed a different behaviour at low and high electrolyte concentrations. At 10 −3 mol.dm −3 NaCl, common thin films were obtained and the thickness decreased with increase in the pressure and rupture occurred at about 3 kPa. At 1 mol.dm −3 NaCl, black films were obtained with much smaller thickness that decreased slowly with the increase in Π and rupture occurred at about 2.7 kPa. These results indicated the transition from electrostatic to steric interaction as the electrolyte concentration was increased.

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confidence: 82%

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confidence: 99%

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Dotchi Exerowa. Foams Stabilized by Hydrophobically-modified Inulin Polymeric Surfactant

Христов¹,

Gotchew²,

Petkova³

et al. 2013

Proceeding BAS

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“…15 It is capable of measuring surface forces on the order of piconewtons at nanometer length scales. The interaction between glass spheres that were attached to the AFM cantilever and glass plates (both hydrophobized using dichlorodimethylsilane) and containing adsorbed layers of hydrophobically modified inulin (INUTEC SP1) was measured as a function of INUTEC SP1 concentration in water and at various Na 2 SO 4 concentrations.…”

Section: ç Experimental Methods For Direct Measurement Of Interactionmentioning

confidence: 99%

Direct Measurement of Interaction Forces between Adsorbed Polymer Layers

Tadros¹

2012

Chemistry Letters

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The interaction forces between adsorbed layers of two graft copolymers were directly measured using surface force apparatus and atomic force microscopy. Two types of graft copolymers that were adsorbed on hydrophobic surfaces were used: (i) a graft copolymer consisting of poly(methyl methacrylate)/poly(methacrylic acid) backbone (the B chain) on which several poly(ethylene oxide) chains are grafted (to be referred to as PMMA/PEO n ) and (ii) a graft copolymer consisting of inulin (linear polyfructose with degree of polymerization greater than 23) (the A chain) on which several C 12 chains are grafted (INUTEC SP1). In the first case, adsorbed layers of the graft copolymer were obtained on mica sheets and the interaction forces were measured using the surface force apparatus. In the second case, the interaction forces were measured using atomic force microscopy (AFM). For this purpose, a hydrophobically modified glass sphere was attached to the tip of the cantilever of the AFM and the glass plate was also made hydrophobic. Both the sphere and the glass plate contained an adsorbed layer of INUTEC SP1. The curves of energy E(D) versus distance D for the graft copolymer of PMMA/PEO n between mica surfaces bearing the graft copolymer could be used to estimate the interaction energy between flat surfaces, by using Derjaguin approximation for cross cylinders. The results were compared with the theoretical calculations using de Gennes scaling theory. The agreement between experimental results and theoretical calculations was satisfactory. The same graft copolymer was used in latex dispersions, and the high frequency modulus G¤ £ was measured as a function of the volume fraction º of the dispersion. This high-frequency modulus could be related to the potential of mean force. In this way, one could compare the results obtained from rheology and those obtained from direct measurement of interaction forces. In the AFM method, the interaction forces are measured in the contact area between two surfaces, i.e., the surfaces of a spherical glass particle and a glass plate. The glass spheres and plates were hydrophobized using dichlorodimethylsilane. Results were obtained for adsorbed layers of INUTEC SP1 in water and in the presence of various concentrations of Na 2 SO 4 (0.3, 0.8, 1.0, and 1.5 mol dm ¹3). All results showed a rapid increase in force with a decrease in the separation distance, and the forces were repulsive up to the highest Na 2 SO 4 concentration. This explains the high stability of dispersions when using INUTEC SP1 as the stabilizer. Ç IntroductionPolymeric surfactants of the type AB, ABA block, and BA n or AB n are the most effective stabilizers for dispersions. The "anchor" chains B are chosen to be highly insoluble in the medium (with a FloryHuggins interaction parameter » > 0.5) and to be strongly adsorbed on the particle or droplet surface. The stabilizing chains A are chosen to be highly soluble in the medium and strongly solvated by its molecules (» < 0.5).The stabilizing mechanism arises from t...

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“…The adsorbed layer thickness measured by AFM was about 9 nm in water and it is decreased to about 3 nm in 1.5 mol dm 23 Na 2 SO 4 . 6 The preparation of latex dispersions using polymeric surfactants, at high solid content, results in large particles, which are also polydisperse. This could be due to the slow diffusion of the high-molecular weight surfactants to the solid/liquid interface.…”

Section: Introductionmentioning

confidence: 99%

Emulsion polymerization of styrene using mixtures of hydrophobically modified inulin (polyfructose) polymeric surfactant and nonionic surfactants

Nestor

Esquena

Solans

et al. 2008

J of Applied Polymer Sci

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Polystyrene latex dispersions were prepared by emulsion polymerization, using a mixture of hydrophobically modified Inulin (INUTEC 1 SP1) and various nonionic surfactants (cosurfactants). Two series of nonionic surfactants were used, namely Synperonic A (C 13-15 alkyl chain with 7, 11, and 20 moles of ethylene oxide, EO) and Synperonic NP (nonylphenol with 10 and 15 moles of EO). For 5 wt % latex, the INUTEC SP1 concentration was kept constant at 0.0165 wt % and the initiator concentration was also kept constant at 0.0125 wt %, whereas the cosurfactant concentration was varied between 0.1 and 0.5 wt %. With the exception of Synperonic A20, all other cosurfactants showed an initial increase in particle diameter followed by a decreased reaching a value comparable with that obtained using INUTEC SP1 alone. However, A20 produced a continuous reduction in particle diameter with increase of surfactant concentration, reaching a value of 100 nm at 0.5 wt % which is lower than the value obtained using INUTEC SP1 alone (188 nm). In all cases, addition of a cosurfactant enhanced the stability of latexes by coadsorption at the solid-liquid interface. The enhanced stability produced by the addition of cosurfactants to INU-TEC SP1 could be illustrated by using the mixture of INU-TEC SP1 and Synperonic A7 at 40 wt % of styrene latex concentration. In this case, the mixture produced lower particle size, much lower polydispersity index and much higher stability. These results are of significant value for industrial applications.

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Interaction forces between particles stabilized by a hydrophobically modified inulin surfactant

Cited by 48 publications

References 28 publications

Dotchi Exerowa. Foams Stabilized by Hydrophobically-modified Inulin Polymeric Surfactant

Dotchi Exerowa. Foams Stabilized by Hydrophobically-modified Inulin Polymeric Surfactant

Direct Measurement of Interaction Forces between Adsorbed Polymer Layers

Emulsion polymerization of styrene using mixtures of hydrophobically modified inulin (polyfructose) polymeric surfactant and nonionic surfactants

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