Analysis of the Relative Humidity Response of Hydrophilic Polymers for Optical Fiber Sensing

• Type: Article in International Scientific Journal
• Date: 2022

Authors

Dias, B (Author) Other; Carvalho, J (Author) Other; Mendes, JP (Author) Other; de Almeida, JMMM (Author) FCUP; Coelho, LCC (Author) FCUP

Journal

Title: Polymers

Vol. 21

Final page: 439

Publisher: MDPI

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 4 Citations

Other information

Authenticus ID: P-00W-0VV

DOI: 10.3390/polym14030439

Abstract (EN): Relative humidity (RH) monitorization is of extreme importance on scientific and industrial applications, and optical fiber sensors (OFS) may provide adequate solutions. Typically, these kinds of sensors depend on the usage of humidity responsive polymers, thus creating the need for the characterization of the optical and expansion properties of these materials. Four different polymers, namely poly(vinyl alcohol), poly(ethylene glycol), Hydromed (TM) D4 and microbiology agar were characterized and tested using two types of optical sensors. First, optical fiber Fabry-Perot (FP) tips were made, which allow the dynamical measurement of the polymers' response to RH variations, in particular of refractive index, film thickness, and critical deliquescence RH. Using both FP tips and Long-Period fiber gratings, the polymers were then tested as RH sensors, allowing a comparison between the different polymers and the different OFS. For the case of the FP sensors, the PEG tips displayed excellent sensitivity above 80%RH, outperforming the other polymers. In the case of LPFGs, the 10% (wt/wt) PVA one displayed excellent sensitivity in a larger working range (60 to 100%RH), showing a valid alternative to lower RH environment sensing.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14