Description

Using supported ionic-liquid membrane (SILM)-inspired methodologies, we have synthesized, characterized, and developed a humidity sensor by coating a liquid composite material onto a hygroscopic, porous substrate. Similar to pH paper, the sensor responds to the environment’s relative humidity and changes

Using supported ionic-liquid membrane (SILM)-inspired methodologies, we have synthesized, characterized, and developed a humidity sensor by coating a liquid composite material onto a hygroscopic, porous substrate. Similar to pH paper, the sensor responds to the environment’s relative humidity and changes color accordingly. The humidity indicator is prepared by casting a few microliters of low-toxicity reagents on a nontoxic substrate. The sensing material is a newly synthesized liquid composite that comprises a hygroscopic medium for environmental humidity capture and a color indicator that translates the humidity level into a distinct color change. Sodium borohydride was used to form a liquid composite medium, and DenimBlu30 dye was used as a redox indicator. The liquid composite medium provides a hygroscopic response to the relative humidity, and DenimBlu30 translates the chemical changes into a visual change from yellow to blue. The borate–redox dye-based humidity sensor was prepared, and then Fourier transform infrared spectroscopy, differential scanning calorimetry, and image analysis methods were used to characterize the chemical composition, optimize synthesis, and gain insight into the sensor reactivity. Test results indicated that this new sensing material can detect relative humidity in the range of 5–100% in an irreversible manner with good reproducibility and high accuracy. The sensor is a low-cost, highly sensitive, easy-to-use humidity indicator. More importantly, it can be easily packaged with products to monitor humidity levels in pharmaceutical and food packaging.

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Details

Title
  • Colorimetric Humidity Sensor Based on Liquid Composite Materials for the Monitoring of Food and Pharmaceuticals
Contributors
Date Created
2014-09-09
Resource Type
  • Text
  • Collections this item is in
    Identifier
    • Digital object identifier: 10.1021/la502593g
    • Identifier Type
      International standard serial number
      Identifier Value
      0743-7463
    • Identifier Type
      International standard serial number
      Identifier Value
      1520-5827
    Note
    • This document is the Accepted Manuscript version of a Published Work that appeared in final form in
      LANGMUIR, copyright American Chemical Society, after peer review and technical editing by the publisher.
      To access the final published work, see http://dx.doi.org/10.1021/la502593g

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    This is a suggested citation. Consult the appropriate style guide for specific citation guidelines.

    Bridgeman, Devon, Corral, Javier, Quach, Ashley, Xian, Xiaojun, & Forzani, Erica (2014). Colorimetric Humidity Sensor Based on Liquid Composite Materials for the Monitoring of Food and Pharmaceuticals. LANGMUIR, 30(34), 10785-10791. http://dx.doi.org/10.1021/la502593g

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