New analysis of organic gas response for ultra-thin LB films

The electrical properties of maleate copolymer (C/sub 18/MA-VE/sub 2/) Langmuir-Blodgett (LB) films were investigated to develop the gas sensor. The conductivity of C/sub 18/MA-VE/sub 2/ LB films were 10/sup -7/[S/cm] for an in-plane. The change of conductivity was occurred by behavior of organic gases, which mean that the behavior of organic gases could be analyzed using conductivity change and applied to the gas sensor. Also, the new gas sensing system using quartz crystal has been studied. The new analytical variable of resonant resistance, which represents the qualitative changes (or viscoelasticity change) of organic material on quartz crystal, was adopted to analyze the mass sensing properties between quartz crystal and fatty acid LB films. As a result, the resonant frequency change is more sensitive to high molecular weight than to low molecular ones.