Using tip-based fiber optic pH probes for the early detection of degradation in civil infrastructure
This study seeks to characterizes the sensitivity of fiber optic based structurally embedded sensors,specifically to monitor the state of chemical degradation for many types of civil infrastructure including.Fiber Optics Chemical Sensors(FOCS)are optical fibers that are used to monitor and detect the early degradation of civil infrastructure bridges,tunnels and buildings.This study analyzes the efficiency of three different low pH sensors that are sensitive to the ingress of chlorides and acid rain into the structural material.The sensors were doped with phenol red(phenolsulfonphthalein),chlorophenol red and phenol red covalently-linked to 3-trimethylammonium propyl acrylamide chloride(MAPTAC).Dyes were immobilized into 5％ MAPTAC/95％ poly(methyl methacrylate)(PMMA)matrix.The low pH sensors were tested for cross-sensitivity of iron chloride(FeCl3)of 1％,2％ and 3％ media from pH 5.0-pH 7.0.Using UV-VIS spectroscopy,changes in the low pH sensor signal were detected at 550 nm and 575 nm.The efficiency of immobilization of the dyes into a nanoporous charged PMMA-MAPTAC matrix,the cross-sensitivity of the low pH sensor to detect changes in low pH levels and metal chloride concentration was also measured.This paper describes the development of optical fiber pH sensors using a nanoporous functional polymer as coating for the optical fibers.The sensors are designed by physical immobilization of low pH sensitive chromophores within a cationic polymer.Experiments are conducted in the laboratory in aqueous media for monitoring pH levels in moderately acidic levels.Details on indicator immobilization as well as potential cross sensitivity to chloride ions is seen in chlorophenol red at 550 nm.
Fiber Optics Chemical Sensor (FOCS) pH sensors metal chlorides chlorophenol
Narissa Puran Dr. Gamal Khalil Dr. Masoud Ghandehari
Polytechnic University,Department of Chemical and Biological Sciences University of Washington,Department of Chemistry Polytechnic University,Department of Civil Engineering
国际会议
The World Forum on Smart Materials and Smart Structures Technology(SMSST07)(2007年世界智能材料与智能结构技术论坛)
重庆·南京
英文
2007-05-01（万方平台首次上网日期，不代表论文的发表时间）