So as to covalently graft a chemical on a substrate, the GraftFastTM process can be used; the only requirement is that the chemical has at least one aromatic primary amine. In this work, this simple and fast process is presently used to graft dyes that are pH sensitive on an optical fiber, thus creating a pH sensor called optode. The major asset of this grafting process is that the dye is covalently grafted on the fiber, resolving stability issues encountered with other techniques – like physical entrapment or electrostatic interactions. Two different dyes have been successfully grafted on gold lamellas (which are the reference substrates for the GraftFastTM process), and an innovative experimental method to increase the thickness of the dye layer has been developed.
The GraftFast® process is a simple ant quick method to covalently graft a chemical on a substrate, provided that the chemical has an aromatic primary amine. Thus, this method is studied for an application in pH measurement via an optode. The aim of this PhD work, which started in October 2012, is to covalently graft a dye sensible to pH variations on an optical fiber, so as to be able to solve the stability issues encountered with other techniques used to assemble the dye and the optical fiber – like physical entrapment or electrostatic interactions. The work presented here explains the concept of an optode and the GraftFast® process. The first results obtained show the two dyes that will be studied, and that one ot those potential dyes, the neutral red, can be quite efficiently grafted on a gold substrate.