University of Leicester
Browse
U113904.pdf (2.88 MB)

A calorimetric study of adsorption and deaggregation in aqueous solution

Download (2.88 MB)
thesis
posted on 2014-12-15, 10:35 authored by Keith David. Irlam
This thesis reports a study of adsorption of small molecules by macromolecules and the deaggregation of micelles in aqueous solution. These phenomena were investigated using an isothermal titration microcalorimeter.;Procedures are described for the analysis of enthalpograms which characterise the adsorption of anionic surfactants, sodium dodecylsulphate (aq), copper dodecylsulphate(aq) and sodium decylsulphate(aq) by a water soluble polymer Poly (N-vinlypyrrolidone)PVP(aq). The application of equations based on both Langmuir and Frumkin adsorption isotherms are discussed. Characteristics features of the enthalpograms for the adsorption are described using equations developed from the Frumkin equation. The adsorption was endothermic as a consequence of hydrophobic interactions between polymer and surfactant. The analysis describes absorbate-absorbate interactions using enthalpic interaction parameters.;Critical micelle concentrations (cmc) of copper, cadmium and nickel dodecylsulphate(aq) in aqueous solution were measured. The calorimetric plots showed an extrema which corresponded to the cmc which was in close agreement with literature values based on surface tension measurements.;Enthalpograms for deaggregation of micelles formed by alkyl trimethylammonium bromide surfactants were classified into three types, A, B, and C. The classification is based on the shape of the plot of the enthalpy of dilution as a function of surfactant concentration.;The effect of the cmc and the enthalpogram of added benzoates to n-hexadecyltrimethylammonium bromide(aq) was investigated. The cmc was reduced and the classification changed from Type A to Type B in all cases. This pattern was accounted for in terms of adsorption of benzoate ions into the Stern layer of the micelles.

History

Date of award

1998-01-01

Author affiliation

Chemistry

Awarding institution

University of Leicester

Qualification level

  • Doctoral

Qualification name

  • PhD

Language

en

Usage metrics

    University of Leicester Theses

    Categories

    Keywords

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC