| 1. |
- Berg, JM, et al.
(författare)
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Three-component Langmuir-Blodgett films with a controllable degree of polarity
- 1994
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Ingår i: Langmuir. - 0743-7463 .- 1520-5827. ; 10, s. 1225-1234
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Tidskriftsartikel (refereegranskat)abstract
- Two different series of mixed Langmuir-Blodgett (LB) films with a controllable degree of polarity, deposited on mica, have been studied by wetting and surface force techniques. Both series contain of 50% eicosylamine (EA). Films of one series consist of EA, arachidic acid and docosanedioic acid, while those of the other consist of EA, 1-eicosanol and 1,22-docosanediol. Carboxylic acid groups give lower contact angles than hydroxy groups. Concerning the stability of the LB films in aqueous solutions, repeated exposure to a three-phase line and high salt solutions were found to cause breakdown. Surface force measurements on carboxylic acid-containing films show that films with a 0% (contact angle = 113°) and 25% (contact angle ≈ 90°) content of diacid interact with a long-range (hydrophobic) attraction across water. No similar long-range attraction is observed for the 50% case (contact angle ≈ 65°). Surface force measurements also detected instabilities and imperfections of the films.
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| 2. |
- Nordli Börve, KG, et al.
(författare)
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Water-in-crude oil emulsions from the Norwegian continental shelf Part V. A comparative monolayer study of model polymers
- 1992
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Ingår i: Colloids and Surfaces. - 0166-6622 .- 1873-4340. ; 63, s. 241-251
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Tidskriftsartikel (refereegranskat)abstract
- Monomolecular films based on poly(styrene-allylalcohol), PSAA, (mean molecular weight = 1500 g/mol) have been studied by means of the Langmuir technique. PSAA forms a highly compressible film which is not affected by changes in subphase pH. Addition of hexadecylaniline (HDA) and eicosylamine modifies the PSAA film. PSAA/HDA films obey additivity at low surface pressures, but not at pressures exceeding 12 mN/m and at low subphase pH. The mixed monolayers of PSAA and HDA have larger collapse pressures than the single component films. All the unionized films show a relaxation behaviour characteristic for polymer reorganizations in monomolecular films. Addition of 1-butanol and benzylalcohol to the subphase reveals substitution effects with regard to spreading as well as specific incorporation into the films. Model films of PSAA containing additives reproduce to essential parts the film behaviour of the previously investigated, interfacially active fraction of authentic crude oils. There seems to be small deviations with regard to maximal compression and surface activity between authentic crude oils and PSAA-based model systems.
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