Preparation Of Sensitive Film By Sol-gel Method And Its Properties

Porphyrin complexes have become ideal models for the study of porphyrin sensors because of excellent properties of light sensitivity,chemical stability easy modification,especially for that very a little of fluctuate involved could be monitored and be determinated either in the spectroscopy methods of UV-vis, IR, fluorescence, phosphorescence and Laman, or in elctroanalytical method conveniently. Recently, high performance hybrid material of Si02/organosilicone by sol-gel method with low surface energy, heat-resistance, good chemical stability and water resistance, light transparency, etc was expected. the sensor film witch preparaed by sol-gel method has been studied to detect the nerve simulate gases. This sensor film presents high sensitivity, quick response and theminiaturigation. This research work will provide a novel way to quickly detect the nerve agent gas in order to fight against terrorism and chemistry war.In this paper, the basic process and characteristic of the sol-gel theory are first introduced in brief. Then it presents the newly research progresses and the applications of the sol-gel method in coatings and films and complex materials. Then,a novel sensitive substance porphyrin with the property of quick response to nerve agent Sarin simulate dimethylmethylphosphonate(DMMP), DMMP is studied.each kind of porphyrin reacted with DMMP function has uniquely, the only spectrum change signal, according to these signals may carry on the quantitative analysis to DMMP, we selected a series of metalloporphyrins. Porphyrin sensor film were prepared with sol-gel method. The conditions of this new method have been studied. Some technical parameters have been optimized by experiment. The optical properties and surface structures of the film have been characterized. The sensing property of the thin film has been tested.In the selecting senstive substance ,we selected a series of metalloporphyrins.The binding of Zinc-porphyrin to DMMP was investigated by absorance spectrum. The changes of standard molar enthalpies and standard molar entropies of reaction were obtained,The relationship between Zinc-porphyrin and DMMP mechanism providede the reliable theory basis.In the preparation of film, the prepared condition greatly effects the structure and property of resulting materials. When the temperature is 60℃, the vol ration of tetraethylorthosilicate(TEOS),water and hydrochloric acid (1M) is 1:0.16:0.12, the film is uniformity. In the preparation of porphyrin sensitive film, the experimental result indicated that, the vol ration of TEOS and ethanol is 1:2,the rotate speed is 2400r.min-1, the film has good sensitive property and has a absorbency variety of light about 2% to 1x10-7 DMMP. The surface structures of the film have been characterized,the suferance is uniformity. As results of scan-AFM, Zinc-porphyrin molecule is tend to plane structure.Porphyrin sensitive film prepared with sol-gel method have good DMMP sensitive property. When respond to 1x10-3—1x10-12 DMMP, the film's absorbency changes evidently. The film has good repeated property.The senstive film prepared with sol-gel method has better property as loosen holes which have fast DMMP response. The film has excellent sensing property and the method is preferred for the sensor .then work is the sensor arrays . this sensor arrays demonstrate the potential applications for identifying the substanceand their mixture at low concentration.Further work is the chip we designed consisting of a micro sensor array, singnal process circuit and transducer. The sensor will be futher miniaturized, integrated with processing circuit and made intelligent.