Multi-layer film surface functionalized PMF sensor for real-time humidity measurement

Abstract

Real-time monitoring of environmental relative humidity (RH) plays a crucial role in ensuring both the quality of industrial production and the quality of life. In this work, polarization maintaining fiber (PMF) was used as carriers to creatively constructed multi-layer film surface functionalization on its cladding surface. The indium tin oxide (ITO) film and polyvinyl alcohol (PVA) doped graphite oxide (GO) composite polymer constitute multi-layer humidity sensitive film, which has the effect of dual absorption of water and improves the humidity sensitivity. Microporous composite polymer films created by laser processing increase the area for water evaporation and absorption, which improve response speed, and reduce recovery time. The surface functionalized PMF sensor exhibits high sensitivity and rapid response to humidity, achieving bidirectional repeated measurement of 0.28 nm/% within 10 s in the measurement range of 30%-90%, rendering it a reliable means for real-time monitoring of humidity.