Preparation And Application Of Polymer-Quartz Composite Fluorescent Optical Fiber Sensor

The evanescent field is applied to the field of optical fiber sensing and modulation,which has the advantages of simple preparation and high sensitivity.The optical fiber probe based on the evanescent field principle has the advantages of small equipment size,simple preparation process,remote operation and strong anti-electromagnetic interference capability.A composite optical fiber probe prepared by combining a specific polymer cladding material with a quartz optical fiber can not only modulate the light intensity and polarization state of the optical signal transmitted in the optical fiber,but also realize detection of small molecules through the effect of the transmitted light on the optical properties of the polymer material.Therefore,two composite optical fiber were designed and fabricated for light modulation and small molecule detection.Based on the considerations of simple preparation and structural stability of a composite optical fiber,we explored the fabrication process of optical fibers without cladding and fiber tapers with structural and property's stability.In the fabrication,due to the incompatibility between organic and inorganic materials,it was found that there is a problem of phase separation at the interface between the silica fiber and the polymer.In order to overcome this shortage,the photochemical reaction initiated by the evanescent field was adopted to combine chemically organic polymer with inorganic glass fiber at the interface between the two.The method was defined as photo-plating.The reaction conditions and the composition of the precursor solution for the polymerization were found to have effect on the polymerization.Related research work and sensing properties of a composite fiber probe were performed,and details are as follows:1.A ternary copolymer containing polysilsesquioxane(POSS)and azobenzene units was synthesized,then an azobenzene polymer-quartz composite optical fiber polarizer was prepared.Using the photoinduced orientation of azobenzene polymer,the transmitted light intensity and polarization state in composite optical fiber can be modulated.By controlling the refractive index of the coated azobenzene polymer,the modulation range of the optical signal in composite optical fiber can be precisely controlled,which provided the basis of theoretical support and experimental techniques for the next step of research.2.The fabrication process of the fiber cone was explored to obtain an optical fiber taper with stable performance.A functional group can be covalently linked to the surface of optical fiber taper by chemical reaction,so that it can participate in the"click"polymerization of the pre-polymerization induced by the evanescent field.The polymer cladding is bonded to the surface by thiol-ene reaction,which meet the waveguide structure requirement for the polymer-quartz composite optical fiber.In order to achieve a specific application,a crosslinked porous polymer layer containing a tetravinylporphyrin derivative was plated on the surface of the taper to detect the TNT vapor,and an expected result was obtained.3.A fluorescein derivative containing double bond was designed and synthesized,then it was incorporated into the polymer cladding by"click"reaction.Combined with the established optical fiber fluorescence sensing system,the detection of biological parameters,such as pH in biological tissue,was realized.4.The preparation of polymer-quartz composite optical fiber taper probe and its application in human blood and cancer detection were initially explored.Firstly,using a protected polymer-quartz composite optical fiber taper probe to contact the biological sample to be tested,then analyzed the detected fluorescence signal of different biological samples by spectrum analyzer.In this way,some specific applications of the polymer-quartz composite optical fiber taper fluorescent sensor in biomedical detection were realized.