Characterisation of a Nafion film by optical fibre Fabry-Perot interferometry for humidity sensing

Author(s)

Santos, Juliana S. ^[1] ; Raimundo, Jr., Ivo M. ^[1] ; Cordeiro, Cristiano M. B. ^[2] ; Biazoli, Claudecir R. ^[2] ; Gouveia, Carlos A. J. ^[3] ; Jorge, Pedro A. S. ^[3]

Affiliation

^[1] Univ Estadual Campinas, Inst Chem, UNICAMP, BR-13083970 Campinas, SP - Brazil

^[2] Univ Estadual Campinas, Inst Phys Gleb Wataghin, UNICAMP, BR-13083859 Campinas, SP - Brazil

^[3] INESC Porto, P-4169007 Oporto - Portugal

• Document type: Journal article
• Source: SENSORS AND ACTUATORS B-CHEMICAL; v. 196, p. 99-105, JUN 2014.
• Web of Science Citations: 33

Abstract

Nafion has been evaluated as a sensing phase of an optical fibre humidity sensor based on a low-finesse Fabry-Perot interferometer. The sensor was constructed by manual deposition of a drop of a Nafion solution on the tip of a single mode optical fibre, forming a Fabry-Perot resonant cavity. The absorption of water by the Nafion film makes it swells, changing its refractive index and the length of the cavity, which produces a phase shift in the interference signal. The sensitivity, stability and response time of the sensor were evaluated in the RH range from 22 to 80% by analysing the correspondent reflection spectra of the interference fringes. As a result, it was obtained that Nafion can be used as sensing phase of an optical fibre humidity sensor based on optical fibre Fabry-Perot interferometry, presenting a response time of 242 ms (3% RH variation) and a sensitivity of 3.5 nm/%RH. (C) 2014 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 11/00322-2 - Development of an optical sensor for determination of moisture in air and natural gas
• Grantee: Juliana Santiago dos Santos
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 08/57808-1 - National Institute of Advanced Analytical Science and Technology
• Grantee: Celio Pasquini
• Support type: Research Projects - Thematic Grants