A.J. O’Lenick, Jr., Siltech LLC

Key words: surfactants, wetting, surface tension, hydrophilic-lipophilic balance (HLB), Draves Wetting test, dimethicone copolyol, sulfosuccinate diesters, phosphate esters

Abstract: In formulation, the key attributes of surfactants are conditioning, wetting, emulsification, and detergency. This article describes the features of surfactants that provide wetting properties in aqueous systems. Specifically, the properties of interest include surface tension reduction, HLB, molecular weight, branching, and level of ethoxylation. The choice of the best wetting agent depends upon chemical structure and the formulation.

This is the second in a series of four articles that will deal with different topics in the field of surfactants. Surfactants are a major class of materials that provide the functional basis of most personal care products. The term “surfactant” is a word that was coined by contracting two words: surface-active agent.

Surfactants, as surface active agents, are compounds that are active at interfacial surfaces. Surfactants function in a variety of ways, depending upon their chemical structure, but all the surfactant functionalities are driven by the systems in which the surfactant is placed and the need to get to the lowest free energy in the system.

These articles will deal with surfactants from a functional point of view. The function a surfactant brings to a formulation is in fact the reason one chooses the particular surfactant. The articles will address the properties surfactants provide namely: conditioning,1 wetting, detergency, and emulsification.  For the complete article, click on "Purchase this article."