Optical fiber pH sensors based on self-assembled multilayered neutral red coatings

Abstract

The Electrostatic Self Assembly Layer-by-Layer (ESA) technique has been already used for the fabrication of optical fiber pH sensors, the properties of the resultant pH sensitive coatings has been found to be strongly dependent on the fabrication parameters, especially on the pH of the polyelectrolyte solutions used for the deposition of the coatings. In this work the resulting properties of the sensitive coatings have been optimized by changing the parameters of fabrication. Techniques as AFM, for studying the thickness and morphology of the sensing films, and spectroscopy, for studying the composition of the films, were used for the characterization of the devices. Optical fiber pH sensors with response from pH 3 to pH 7 were successfully fabricated.