28 February 2005 Highly processable method for the construction of miniature conducting polymer moisture sensors
Author Affiliations +
A polymer blend incorporating polyaniline (PAn) was used as a sensing medium in the construction of a resistance based humidity sensor. Aniline monomer was polymerised to PAn emeraldine salt (ES) in the presence of poly (butyl acrylate-co-vinyl acetate) and the processable blend was developed by redissolving 1-2 w/w% of the resulting sensing polymer residue in dichloromethane (DCM). Some of this residue was washed in ammonia solution to de-dope the PAn to emeraldine base (EB) to act as a protective layer on the surface of the sensing polymer. This residue was then washed with distilled water until a neutral pH was realised with the waste water, dried and redissolved in DCM at 1-2 w/w% to create a processable blend barrier polymer solution. The final sensor design utilised 125μm polyester insulated platinum wire as conducting electrodes that were dip coated in the PAn ES blend solution and dried in a desiccator. A protective coating was then applied by dip coating in the EB blend solution. The sensors had an overall final thickness of less than 200μm and showed high sensitivity to humidity, low resistance, and good reversibility without hysteresis. The EB protective layer was shown to give more stable and predictable responses to the sensors when placed inside curing epoxies. Polymer based thin film humidity sensors have the advantage that the high processability of the material allows for simple fabrication of a range of geometries including smaller sensor designs. Such sensors may find uses in detecting water content in a number of areas including composite materials, electronic textiles, food/electronics packaging and corrosion detection.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Scott T. McGovern, Scott T. McGovern, Geoffrey M. Spinks, Geoffrey M. Spinks, Gordon G. Wallace, Gordon G. Wallace, "Highly processable method for the construction of miniature conducting polymer moisture sensors", Proc. SPIE 5649, Smart Structures, Devices, and Systems II, (28 February 2005); doi: 10.1117/12.582241; https://doi.org/10.1117/12.582241


Flexible humidity sensors with polymer sorption layer
Proceedings of SPIE (November 09 2016)
From sensitive fabrics to distributed wearable sensors
Proceedings of SPIE (June 11 2000)
Electro-active material (EAM) based bend sensors
Proceedings of SPIE (April 20 2010)
Investigations of a new humidity sensor with polymer film
Proceedings of SPIE (October 19 2006)
The influence of the choice of the cross linking agent...
Proceedings of SPIE (September 21 2003)

Back to Top