A QUARTZ CRYSTAL MICROBALANCE METHOD FOR THE CHARACTERIZATION OF NEW PHOTOCHROMIC MATERIAL

Quartz Crystal Microbalance (QCM) has found numerous applications in many fields including thin-film measurement, chemical analysis, gas sensor, humidity sensor and biosensor. Especially, the development of QCM systems for use in fluids or with viscoelastic deposits has dramatically increased the interest towards this technique. QCM device will be used for measurements of adsorption of synthesized copolymer. The gold sensor has been recognized as excellent indicator of mass changes because of the direct relationship between mass change and resonant frequency response. New maleic anhydride (MA) copolymer with styrene (S) modified by condensative coupling reaction with azo photochrome dye (H2N-C6H4-N=N-C6H4-Cl) was obtained and the results concerning structures were published. The selection of the maleic anhydride copolymer is justify by MA tendency for forming alternant copolymers, what permits to obtain architectures with big degree of structural regularity as well as of the anhydridic group reactivity in reaction with primary amines. During the adsorption process the QCM measures a frequency change that can be associated to a mass change due to adsorption of the copolymer. Quartz crystal microbalance is used to monitor in real-time the polymer adsorption followed by azoic dye adsorption and then copolymer adsorption as well as optimization of interaction processes and determination of solution effects on the analytical signal. Solutions of azoic dye (5.10(-4)g/L, 5.10(-5) g/L and 5.10(-6) g/L in DMF) are adsorbed at gold electrodes of QCM and the sensor responses are estimated through decrease of QCM frequency. Also, the response of the sensor at MA-S copolymer (solution 5.10(-4) g/L, 5.10(-5) g/L and 5.10(-6) g/L in DMF) is fast, large, and reversible. This research showed the fact that the quartz crystal microbalance is a modern alternative to study some physical and chemical properties of synthesized copolymer. Additionally, infrared spectroscopy and nuclear magnetic resonance (NMR) has been used to compare the properties of the polymer, copolymer and dye.