A kind of in-tube growth doped state or filled mesoporous polyaniline gas sensor and its preparation method

Abstract

The invention discloses a sensor with doped-state mesoporous polyaniline gas growing in a tube or a filled mesoporous polyaniline gas sensor, and preparation methods thereof. According to the presentinvention, a tube having any sizes and made of any materials is used as a matrix, doped state polyaniline grows in the tube or the tube is filled with mesoporous polyaniline, and electrodes and electric-conduction lead-out ends are prepared to form the sensor; the preparation method comprises: modifying the inner wall of a tube, introducing an initiator and a doped-state aniline solution, controlling the film thickness according to the amounts and the concentrations of the doped-state aniline and the initiator, or directly filling the tube with mesoporous polyaniline, producing electrodes on both ends of the tube, and winding the outer wall electrode with a metal fine wire to connect a resistance detecting device; when the concentration of the to-be-detected gas is extremely low and the resistance change is not obvious after the contact with polyaniline, the plurality of the sensors can be connected in parallel to form the cluster sensor so as to substantially reduce the initial resistance and improve the sensitivity; and the sensor has advantages of high detection sensitivity to all concentration gases, extremely short response time, fast recovery, good stability, convenient use,convenient carrying high commercial prospect and the like.

Description

technical field [0001] The invention belongs to the technical field of gas sensors, in particular to an in-tube grown doped state or filled mesoporous polyaniline gas sensor and a preparation method thereof. Background technique [0002] Ammonia, sulfur dioxide, nitrogen oxides (NOx) and other gases are irritating odorous gases that are harmful to the environment or pollutants that are harmful to human health in the atmosphere. Therefore, the development of corresponding gas sensors can effectively and accurately distinguish pollution source gases and their concentrations at the initial stage of gas leakage (ppm, ppb, ppt level concentration) and issue corresponding alarms, which is of great significance to environmental monitoring of human health. The currently known gas sensors mostly use a limited selection of materials such as flake glass ceramics as substrates, and prepare planar films by spin coating or electrochemical deposition. The combination is not tight enough, t...

AI Technical Summary

Problems solved by technology

The currently known gas sensors mostly use a limited selection of materials such as flake glass ceramics as substrates, and prepare planar films by spin coating or electrochemical deposition. The combination is not tight enough, the preparation conditions are many, and the prepared sensor space occupies relatively Large means that the specific surface contact area is small, and the size and thickness requirements cannot be changed arbitrarily according to the demand. Even if it responds to gases with ppm, ppb, and ppt concentration levels, there is still a lot of room for improvement in response and recovery time

[0003] For the polyaniline sensitive layer prepared by the chemical oxidation method, it is mostly initiated by APS (ammonium persulfate), doped with a single proton acid or an inorganic oxide such as SnO 2 , WO 3 For doped polyaniline, the former has a slow formation rate and is prone to reverse doping in a high-temperature environment, which affects the detection accuracy of gas concentration. Traditional polyaniline sensors still have a large gap in the hard indicators such as gas response time, recovery time, and stability, which cannot meet the current environment and human health's idea that the sensor should be controlled in the early stage of harmful gas leakage.

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