Fabrication Of Affinity Coatings On The Surface Of Optical Fibers And The Monitoring Technique Of Corrosive Parameters

This paper represents the fabrication of the affinity coating on the long period grating surface and its use on monitoring of cupric ions.The key point of this task is to choose a proper material and adopt appropriate reaction conditions accordingly. Carboxymethyl cellulose (CMC), with its chelating structure has an affinity for cupric ions. This chelating polymer can be applied on the surface of the LPG sensor as affinity coating after a series of chemical reactions.Since CMC cannot be directly applied to the surface of LPG sensor, a coupling agent must be found that will act as a bridge on the interface of inorganic and organic materials to enhance the cohesive strength. (3-Aminopropyl)triethoxysilane, a coupling agent with two different functional groups, can react with hydroxyl groups and CMC respectively, which can be used to apply CMC on the surface of the LPG sensor.CMC was first applied on the surface of quartz glass, since it has the similar composition as the LPG fiber. To get a better affinity coating, many experimental conditions are tested, taking all possible conditions into consideration: selection of appropriate solution, control of the reaction time, optimization of the temperature of reaction and activation of the hydroxyl groups. Scanning electronic microscope (SEM) and electronic dispersive X-ray detector (EDX) were used to confirm the reliability of the testing result, which can be used to help choose an optimal processing condition.