Hydrogel-coated fiber Bragg grating sensor for pH monitoring

Abstract

We present a fiber-optic wavelength-modulated sensor for pH applications. Fiber Bragg grating (FBG) is functionalized with a stimulus-responsive hydrogel that induces a strain on FBG due to mechanical expansion of the gel in response to ambient pH changes. The gel is synthesized from the blends of poly (vinyl alcohol)/poly (acrylic acid). The induced strain results in a shift of FBG reflected peak that is monitored by an interrogator. The sensor system shows good linearity in the acidic pH range of 3 to 7 with a sensitivity of 12.16 pm∕pH. In addition, it shows good repeatability and oscillator behavior, which proves it to be fit for pH sensing applications. Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 06/27/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Optical Engineering 066112-2 June 2016 • Vol. 55(6) Pabbisetti and Madhuvarasu: Hydrogel-coated fiber Bragg grating sensor for pH monitoring Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 06/27/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Optical Engineering 066112-7 June 2016 • Vol. 55(6) Pabbisetti and Madhuvarasu: Hydrogel-coated fiber Bragg grating sensor for pH monitoring Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 06/27/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

Effects of Solvent Etching on PMMA Microstructured Optical Fiber Bragg Grating

“…decrease the amount of axial force needed to produce a certain value of strain. For instance, this is highly useful when using the FBG in combination with a transducer for chemical sensing and biosensing applications [5]- [8]. This can be achieved by reducing A in eq.…”

FBG Multifunctional pH Sensor - Monitoring the pH Rain in Cultural Heritage

“…Fiber Bragg grating (FBG) sensors coated with pH-sensitive hydrogel have been studied through a simulation, which showed that they can provide a linear response in the pH range of 5 to 7 with a sensitivity of 0.164 nm/pH unit [9], [10]. Optical pH sensors have advantages compared to the conventional ones, being free from electromagnetic interference, having wide bandwidth, being open to miniaturization, real-time measurement and remote sensing [11]- [13].…”

Optical Fiber Sensors: Working Principle, Applications, and Limitations

“…Multilayers of PVA/PAA were deposited on FBGs by the dip‐coating method for developing a pH sensor. [ 19 ] The hydroxyl groups of PVA and the carboxyl groups of PAA were cross‐linked by heating up the multilayers. The fiber sensor showed a linear response to pH in the range of 3–7, presenting a sensitivity of 0.0122 nm pH −1 resulting from the change of the swelling degree of the hydrogel in different pH conditions.…”