- by Hans Oskarsson, Surfactants Europe

The adsorption of cationic surfactants at surfaces is an important process, essential for a large number of surfactant applications. Quartz crystal microbalance (QCM) and surface plasmon resonance (SPR) are two new methods to study adsorption of surfactants at the solid/liquid interface. SPR is an optical method of measuring small changes in the refractive index at gold surfaces onto which self-assembled monolayers (SAMs) of alkanethiols have been created.

Adsorption of ethoxylated and quaternized octadecylamines has been investigated on both hydrophobic and hydrophilic surfaces. This study demonstrates the usefulness of SAM-surfaces as a tool to vary the nature of substrates and in combination with SPR efficiently measure the amount adsorbed at the surface.

This work was published in Journal of Colloids and Interface Science. For further information contact Hans Oskarsson; hans.oskarsson@sc.akzonobel.com.