An Optical Fiber Sensor Coated with Electrospinning Polyvinyl Alcohol/Carbon Nanotubes Composite Film.

Jinze Li,Hao Sun,Liming Wang,Jianqi Zhang,Li Deng,Xin Liu,Tianhong Ma

doi:10.3390/s20236996

Abstract

A fiber-optics tapered sensor that is covered by an electrospinning polyvinyl alcohol (PVA) nanofiber film, is demonstrated to measure humidity and temperature simultaneously. A section multi-mode fiber (MMF) was sandwiched between two leading-in and out single mode fibers (SMFs), which was further tapered down to 29 μm to promote the humidity sensitivity of the sensor. A thin layer of electrospinning PVA nanofiber film was uniformly coated on the MMF taper region by electrospinning technology. In order to promote the humidity sensitivity and mechanical strength of electrospinning nanofibers, the carbon nanotubes (CNTs) were mixed into PVA to formed PVA/CNTs composite nanofiber film. A Fiber Bragg Grating (FBG) was cascaded with the humidity sensing fiber to monitor the ambient temperature simultaneously. The addition of CNTs effectively eliminated the cracks on the electrospinning nanofiber and made it more uniform and smoother. As experimental results show, the humidity sensitivity of the sensor with PVA/CNTs film was 0.0484 dB/%RH, an improvement of 31.16% compared to that of the sensor with PVA film, for which sensitivity is 0.0369 dB/%RH. The nanofiber humidity-sensitive film constructed using electrospinning had a satisfactory humidity response, special 3D structure and extensive application prospect.

Highlights

Humidity monitoring is important in the industrial, agricultural, medical, chemical, and construction fields [1,2,3,4]
The optical fiber humidity sensor can overcome the influence of these extreme environments and work correctly
Experimental results showsensitivity that the addition of carbon nanotubes (CNTs) improves theincreases humiditythe sensitivity of the polyvinyl alcohol (PVA) of improves the humidity of the PVA

Summary

Introduction

Humidity monitoring is important in the industrial, agricultural, medical, chemical, and construction fields [1,2,3,4]. The demand for humidity sensors in various industries has recently promoted continuous research on different types of optical fiber humidity sensors [5]. It is necessary to develop a humidity sensor with high sensitivity and a high humidity response range. Intense electromagnetic radiation, high temperature and high-pressure environments, traditional humidity sensors will not work correctly. The optical fiber humidity sensor can overcome the influence of these extreme environments and work correctly. The development of optical fiber humidity sensors has received increasingly more attention

Methods

Results

Conclusion