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- Folmer, BM, et al.
(författare)
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Micellization and adsorption of a series of fatty amide ethoxylates
- 2001
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 242, s. 404-410
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Tidskriftsartikel (refereegranskat)abstract
- An in-depth study of the adsorption and micellization behaviour of a series of fatty amide ethoxylates is presented. The effect of the amide bond is studied as well as variations in unsaturations in the hydrocarbon chain and in the length of the oxyethylene headgroup. Ellipsometry is used to determine adsorption on a hydrophobic silica plate while 1H-NMR self-diffusion is used to study micelle size and structure. The amide bond was found to increase the hydrophilicity of the surfactant leading to less favourable packing at the interface. The micelles formed by these surfactants were more compact, compared to alcohol ethoxylates with the same hydrophobe. Effects of unsaturations on the interfacial packing were not be observed. The micelle structure was somewhat affected by the unsaturations due to increased bulkiness of the surfactant hydrophobe.
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- Folmer, BM
(författare)
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Sterol surfactants: from synthesis to applications
- 2003
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Ingår i: Advances in Colloid and Interface Science. - 0001-8686 .- 1873-3727. ; 103, s. 99-119
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Tidskriftsartikel (refereegranskat)abstract
- An overview is given of sterol surfactants, including raw material aspects, classification and synthesis routes, physico-chemical behaviour and applications in pharmaceuticals and cosmetics.
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4. |
- Folmer, BM, et al.
(författare)
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The cross sectional headgroup area of nonionic surfactants; The influence of polydispersity
- 2001
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Ingår i: Colloids and Surfaces A. - 0927-7757 .- 1873-4359. ; 180, s. 187-191
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Tidskriftsartikel (refereegranskat)abstract
- In this work we have measured surface tension as a function of concentration of pure and technical nonionic ethoxylated surfactants. CMC values, surface tension at the CMC and the cross sectional headgroup areas are compared. It is shown that the CMC does not depend significantly on the polydispersity of the polyoxyethylene chain. However, the surfactant headgroup area, as determined from the surface tension plots, are much smaller for polydisperse surfactants than for homologue pure surfactants. This is due to the selective adsorption of the shorter polyoxyethylene species at the surface. For the same reason the surface tension at the CMC is lower for technical surfactants than for homologue pure species.
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5. |
- Folmer, BM, et al.
(författare)
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The physicochemical behavior of phytosterol ethoxylates
- 1999
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 213, s. 112-120
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Tidskriftsartikel (refereegranskat)abstract
- In this work the physicochemical behavior of a series of phytosterol ethoxylates in water is presented. The influence of the length of the polyoxyethylene chain is studied. The surfactant solutions have been examined by means of birifringent microscopy, surface tension, self diffusion 1H-NMR, dynamic and static light scattering, and rheology. The surfactants with a hydrophilic chain of 10 oxyethylene units or more gave a micellar region. The CMC values were generally very low and a reverse relationship between the CMC value and the polyoxyethylene chain length was obtained. The time required to reach equilibrium surface tension was very long, more then 150 minutes. For the hydrophobic surfactants large lamellar regions appeared while for the more hydrophilic surfactants cubic and hexagonal structures were present which remained stable up to temperatures of 100°C. In the micellar region prolate aggregates were formed which showed 'ghostlike' behavior, consisting of crossliked micelles with very fast relaxation times.
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6. |
- Folmer, BM, et al.
(författare)
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The physicochemical behavior of phytosterol ethoxylates
- 1999
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Ingår i: JOURNAL OF COLLOID AND INTERFACE SCIENCE. - : ACADEMIC PRESS INC. - 0021-9797. ; 213:1, s. 112-120
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this work the physicochemical behavior of a series of phytosterol ethoxylates in water is presented. The influence of the length of the polyoxyethylene chain is studied. The surfactant solutions have been examined by means of birefringent microscopy, s
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