NANOGRAVIMETRIC GAUGE FOR SURFACE-DENSITY MEASUREMENTS AND DEPOSITION ANALYSIS OF LANGMUIR-BLODGETT-FILMS

A simple tool for surface density measurements of deposited Langmuir-Blodgett films based on the principle of nanogravimetric piezoelectric resonators has been developed. This device can be very useful for monitoring the quality of the deposited films by checking the functional dependence of the surface density upon the number of deposited layers. Moreover, knowing the molecular weight and the area per molecule of the deposited compound, it is also possible to calculate the packing degree. This parameter can provide a direct method for comparing different techniques of deposition and film formation, taking into account the different behavior of the molecules at the air/water interface and on the solid substrate. The developed tool can, from another point of view, provide information on the area-per-molecule of those samples whose properties do not allow its estimation by usual pressure/area isotherms.