Chemical detectors Optical fibers Plastic coating Thin films--Optical properties
An intrinsic fiber optic chemical sensor has been designed and developed by using a polymer material as a modified fiber cladding. The sensor is constructed by replacing a certain portion of the original cladding with a chemically sensitive material, specifically, polyaniline or polypyrrole. Both the light absorption coefficient and the refractive index of the polymers change upon the exposure to different chemical vapors. These changes induce the optical intensity modulation of the fiber optic sensor. Polyaniline or polypyrrole is coated as the modified cladding by either spin-cast or in-situ deposition method for sensing HCl, NH3, H 2O2, and H4N2 vapors. All sensors show rapid and strong response to the chemical vapors. Thus, these sensors demonstrate that polyaniline and polypyrrole are viable candidate materials for the detection of volatile toxic gases. Sensors exhibit better performance when correct parameters, such as modification area, in-situ deposition time, and spin-rate, are used in the cladding modification process. The reversibility of the sensor depends on the reaction between the modified cladding material and the chemical vapors. Polyaniline cladding has better reversibility than polypyrrole. The optimized sensor response and sensitivity can be achieved by selecting an incident light with suitable wavelength, power, and incident angle.
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Title
Polymer materials as modified optical fiber cladding for chemical sensors
Creators
Jianming Yuan
Contributors
Mahmoud El-Sherif (Advisor) - Drexel University, Drexel University (1970-)
Awarding Institution
Drexel University
Degree Awarded
Doctor of Philosophy (Ph.D.)
Publisher
Drexel University; Philadelphia, Pennsylvania
Number of pages
xiv, 147 pages
Resource Type
Dissertation
Language
English
Academic Unit
College of Engineering (1970-2026); Drexel University