THE STRUCTURE AND COMPOSITION OF MIXED CATIONIC AND NONIONIC SURFACTANT LAYERS ADSORBED AT THE HYDROPHILIC SILICON SURFACE

The use of specular neutron reflection to determine the structure and composition of mixed surfactant layers adsorbed at the liquid-solid in terface is described. The structure of the bilayer formed at the hydro philic silicon-aqueous solution interface by the mixed cationic/non-io nic surfactant mixture of hexadecyltrimethyl ammonium bromide, C(16)TA B, and hexaethylene glycol monododecyl ether, C12E6, is described. The role of measurements using different isotopic (hydrogen/deuterium) la belling of the surfactant and solvent is highlighted, and the need to accurately characterise the native oxide layer on the surface of the s ilicon is discussed. (C) 1998 Elsevier Science B.V. All rights reserve d.