## LSU Historical Dissertations and Theses

1997

Dissertation

#### Degree Name

Doctor of Philosophy (PhD)

Chemistry

William H. Daly

#### Abstract

Polymer and surfactant interactions have been a subject of intense research due to industrial applications utilizing a polymer-surfactant system, such as cosmetic formulation. A series of aminoalkylcarbamoyl cellulose derivatives were prepared from the amidation of methylcarboxymethyl cellulose. These derivatives were quaternized with either iodomethane, or hydroxypropyl trimethylammonium chloride, or epichlorohydrin and dimethylamine to yield polyquaternary ammonium salts. The focus of this dissertation is the characterization of a family of these compounds based on N,N$\sp\prime$,-dimethylethylene diamine. As these compounds are similar to Polyquaternium 10, a quaternized hydroxyethyl cellulose derivative, the solution properties have been characterized; antimicrobial activity and keratin affinity have been determined. Viscosity measurements indicated that derivatives containing a low number of cationic charges per graft and shorter graft length have the highest viscosity. Solubility studies showed that the polymers precipitate at their respective theoretical charge neutralization ratios at concentrations of polymer and anionic surfactant greater than 0.010%. At low polymer concentrations, a fixed concentration of sodium dodecyl sulfate was necessary to precipitate the complexes. The critical mole fraction of anionic surfactant necessary to cause precipitation of polymer-mixed surfactant micelle complexes was dependent upon polymer flexibility, charge density and polymer concentration. Changes in pyrene fluorescence intensity indicated that the micellar regions formed in these complexes were more hydrophilic than free micelles. Dynamic light scattering showed that systems containing Polyquaternium 10 were nearly monodisperse; whereas, systems containing our polymers were polydisperse. The Polyquaternium 10-mixed surfactant micelle complex exhibited a different temperature response than complexes formed with the aminoalkylcarbamoyl cellulose derivatives. Surface tension studies showed evidence of three interaction zones which were present regardless of polymer structure or charge density. Foam studies indicated that the system containing Polyquaternium 10 required more polymer to produce maximal foamability of SDS than either of our polymers. Bactericidal activity of the polymers against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was determined. The results indicated that quaternary polymers may have a dual role in cosmetic products as preservatives and thickeners. Finally, scanning electron microscopy indicated that the binding of the polymers to the hair fibers was not uniform in all cases.

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