Thermodynamics of micellization of nonionic saccharide-based N-acyl-N-alkylaldosylamine and N-acyl-N-alkylamino-1-deoxyalditol surfactants

Thermodynamics of micellization of nonionic saccharide-based N-acyl-N-alkylaldosylamine and N-acyl-N-alkylamino-1-deoxyalditol surfactants

Pestman, J.M.
Kevelam, J.
Blandamer, M.J.
van Doren, H.A.
Kellogg, R.M.
Engberts, J.B.F.N.
Centraal Instituut voor Voedingsonderzoek TNO

1999

Eight homologous series of nonionic carbohydrate-derived surfactants in which the alkyl chains are linked through N-acylated amine bonds were synthesized, and their critical micelle concentrations (cmc's) and standard enthalpies of micellization were determined using titration microcalorimetry. Gibbs energies of micellization (ΔmicG°) were calculated from the critical micelle concentrations. N-Acyl-N-alkylaldosylamines (acyl = acetyl/propionyl, aldosyl = glucosyl/lactosyl) and N-acyl-N-alkylamino-1-deoxyalditols (acyl = acetyl/propionyl, alditol = glucitol/lactitol) with alkyl chain lengths of 8, 10, and 12 carbon atoms show a 10-fold decrease in cmc when the length of the chain is increased by two methylene groups. The enthalpograms for the C8 analogs are more complicated than those for the C10 and C12 analogs. Therefore, the enthalpograms were modeled using a computer-based program which takes account of the nonideal properties of the solutions, yielding enthalpies of micelle formation. Increments in the thermodynamic parameters show satisfactory self-consistency. Each CH2 group contributes -2.4 kJ mol-1 to ΔmicH°, ΔmicG°-(CH2) is -3.0 kJ mol-1 for each series, and TΔmicS°(CH2) is 0.7 kJ mol-1 at 40 °C. Although the change in entropy is the main driving force for micellization, the enthalpy of micellization may also contribute significantly to the Gibbs energy of micellization, particularly for longer alkyl chains.

Nutrition
Calorimetry
Carbohydrates
Chemical bonds
Critical micelle concentration
Enthalpy
Entropy
Gibbs free energy
Molecular structure
Nitrogen compounds
Synthesis (chemical)
Titration
Acylalkylaldosylamine
Acylalkylaminodeoxyalditol
Surface active agents

http://resolver.tudelft.nl/uuid:886acc12-a231-4bfa-b06c-12f86d8adf8c

https://doi.org/10.1021/la981404w

234981

ACS

0743-7463

Langmuir, 15 (6), 2009-2014

article