Structure and Property Correlations of Surface-Active Agents in the Control of Colloidal Behavior in Home/Personal Care and Biochemical Systems

Complexity in Home and Personal Care appears in several forms – the product, the substrate, and their interactions. The aim of this thesis is to investigate strategies for selecting effective surface-active agents (surfactants) that can be used in combination with other active ingredients in industry-relevant formulations deployed in the personal care sector. This thesis is composed of three parts, each of which involves a study of a complex natural system as it is affected by the addition of a complex chemical mixture. This is done in an effort to expose key features of the design rules for engineering the chemical mixture to enhance baseline performance via synergistic interactions of the formulation components and the natural system components. The first topic is an investigation on how the effectiveness of surface-active agents for removing a mixture of hydrophobic and hydrophilic soils from fabrics is related to the surfactants' physical-chemical features. The second topic is an exploration of compatible surfactant-enzyme systems that can be used in various industrial applications, where the behavior at a variety of interfaces is concomitantly important. Here, the focus is on the effect of surfactant structure and properties on enzyme function (i.e., activity), structural mobility and stability. The third topic is an investigation on the usefulness of micro-Raman spectroscopy for determining in situ chemical information that relates to the effects of a variety of surfactants on the mechanical and textural features of skin.