Abstract
In this paper, two different pH sensors based on the deposition of nanometric scale polymeric films onto the surface of a long-period fiber grating (LPFG) have been studied and compared. An electrostatic self-assembled (ESA) method has been used to create sensitive films with an optimal overlay thickness. Two types of sensors have been designed: The first one is based on polyallylamine hydrochloride (PAH), polyacrylic acid (PAA), and the second one was done incorporating the pigment Prussian blue (PB) in the PAH/PAA matrix. A theoretical model of multilayer cylindrical waveguides based on coupled-mode theory has been used to predict the position of the attenuation bands as a function of the overlay thickness. Both sensors were tested and compared in terms of sensitivity and response time. A faster response was obtained with the introduction of PB particles in the polymeric matrix. Linear sensors in the pH range 4–7 were obtained, showing good repeatability and high sensitivity.
| Original language | English |
|---|---|
| Pages (from-to) | 455-463 |
| Number of pages | 9 |
| Journal | IEEE Sensors Journal |
| Volume | 7 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 7 Mar 2007 |
| Externally published | Yes |
Keywords
- Coupled-mode analysis
- electrostatic self-assembly (ESA)
- long-period fiber gratings
- nanophotonics
- nanostructured materials
- optical fiber sensors
- pH sensor