Preparation method of sensitive film for detecting chloride ion optical fiber sensor in concrete pore solution

Abstract

The invention provides a method for preparing a sensitive film of an optical fiber sensor for detecting chloride ions in a concrete pore solution. Polytetrafluoroethylene, polyvinylidene fluoride or polyimide and graphene are dissolved in DMSO to obtain a precursor solution; Grafting modifier, after vigorous stirring in an oil bath, dissolve in 2 to 5 times the mass of DMF to obtain a mother liquor solution; add inorganic nanoparticles and a certain weight of chloride ion fluorescent probe powder, and use ultrasonic dispersion immediately after magnetic stirring Dispersed with an instrument to obtain a homogeneous spray film liquid, and electrostatically sprayed to prepare a sensitive film; large specific surface area, good hydrophilicity, excellent mechanical properties and chemical stability, especially suitable for civil engineering applications such as concrete Detection of chloride ions in harsh environments; the fiber optic sensor using the chlorine-sensitive membrane responds very quickly and sensitively to chloride ions, and can detect the content of chloride ions in concrete in real time.

Description

technical field [0001] The invention belongs to the technical field of chloride ion detection in civil engineering concrete, and relates to the chloride ion optical fiber sensor technology in concrete pore solution, in particular to a sensitive film of the chloride ion optical fiber sensor. Background technique [0002] Large-scale civil engineering facilities such as bridges, tunnels, dams, and embankments have the characteristics of long design life, high cost, harsh service environment, wide coverage area, and large volume. The time-varying evolution effect is significant, and the damage location is concealed. Corrosion of reinforced concrete structures is one of the most concerned issues, which will cause deterioration of structural reliability, shorten service life, and even cause huge safety hazards. Steel bar corrosion develops slowly by pitting corrosion, and the effect of pitting corrosion on the entire structure is not significant in the initial stage of corrosion...

AI Technical Summary

Problems solved by technology

[0004] The current research is mainly to use the fluorescent indicator of chloride ion fixed on the surface or end of the optical fiber for monitoring, which may cause the fluorescent indicator to fall off or fall off after a long time of use of the optical fiber probe, especially in complex environments such as concrete interiors. Dissolution problem

CN105510293A discloses a fluorescent optical fiber sensor for detecting chloride ion concentration in concrete, which uses a fluorescence ratio method combining a balanced optical fiber probe and a measuring optical fiber probe to solve the chloride ion concentration measurement caused by light source intensity fluctuations or photobleaching of fluorescent materials inaccurate question

However, the fluorescent probe itself has the phenomenon of photobleaching of the fluorescence intensity, and the need to fix it in a thin film to be used in a sensor needs to be further studied.

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