OPTICAL FIBER PH SENSOR BASED ON SELF-ASSEMBLED PDDA/PAA NANOCOATING

Bobo Gu, Ming-Jie Yin, A. Ping Zhang, Jin-Wen Qian

Abstract

A new fiber-optic pH sensor based on a thin-core fiber modal interferometer (TCFMI) with electrostatic self-assembled nanocoating is presented in this paper. By using layer-by-layer (LBL) electrostatic self-assembly technique, polydiallyldimethylammonium chloride (PDDA) and poly(acrylic acid) (PAA) are deposited on the side surface of TCFMI for pH sensing. Quartz crystal microbalance (QCM) is employed to monitor the thickness growth, and the morphology of the nanocoating is characterized by using atomic force microscopy (AFM). A linear, fast, and monotonic response of the sensor in both acidic and alkaline solutions (pH range: 2~10) with resolution of 0.0082 pH unit was experimentally demonstrated.

Keywords

Fiber-optic pH sensor, Fiber modal interferometer, Electrostatic self-assembly

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DOI

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IMEKO TC

TC2 - Photonics

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