ION INCLUSION INTO LANGMUIR-BLODGETT-FILMS STUDIED ON A QUARTZ - CRYSTAL MICROBALANCE

The potential of a simple quartz crystal microbalance (QCM) system for the study of ion inclusion into Langmuir-Blodgett (LB) films is demon strated for cadmium docosanoate multilayers over a range of pH values which cover the range of unbound acid films to the high pH salt films. The reproducibility of the deposition process, the number of ions bou nd per fatty acid molecule and the inclusion of water into the film ar e measured as a function of pH and compared with values from X-ray ref lection measurements. The microscopic drying process and its relevance to film reproducibility are also investigated. There is a slight, sig nificant change in the areal density of the fatty acid component as ac id films are converted to fully bound ionic soap films, in addition to the well documented change in the unit-cell c-axis.