Langmuir-Blodgett films of composite calixarene/polyphenylsulphide compounds for ozone sensing

Composite Langmuir-Blodgett films of polyphenylsulphide/calix-4-resorcinarene (PPS/C-4-RA) with different molar ratios were deposited on quartz crystals and silicon wafers. Using ellipsometric and quartz-crystal microbalance methods, the thickness and mass of the film were found to increase linearly with the number of deposited layers. An optimal molar ratio for the deposition of C-4-RA/PPS films was found to be about 1/3, yielding a thickness of 9,25nm/layer and frequency changes of 1.5kHz/layer corresponding to surface concentration of PPS of 2 . 10(22)m(-2). The frequency of C-4-RA/PPS-coated quartz crystals decreases with time on exposure to ozone. Both the mass gain and concentration of oxygen appearing in the film during oxidation were calculated. The highest response was observed for LB films with the C-4-RA/PPS molar ratio of 1/3. An average ozone concentration of 0.5ppm was recorded by QCM transducers near a standard photocopier

Surface plasmon resonance studies on spin coated films of azobenzene-substituted calix-4-resorcinarene molecules

Thin films of tetra-undecyl-tetra-p-nitrophenylazocalix(4)resorcinarene (Azol) molecules were deposited on different substrates by the spin coating method. The refractive index of spun films is found to be 1.494 from surface plasmon resonance (SPR) experiments on the sample in contact with two different dielectric media: air and high purity water. The thickness of films decreases with the increase in the spin speed as a -2/3 power law but rises linearly with the concentration. These observations are in agreement with hydrodynamic theory for spinning of a low-viscosity and highly volatile liquid

A Surface Scientist's view on Spectroscopic Ellipsometry

none1noneMaurizio CanepaCanepa, Maurizi