This article investigates organic and polymeric materials, printing technology and sensing principles towards a reliable printed wearable pH sensor realised on textile substrates. This work systematically makes a literature study and experimental work of three different organic and polymeric material based pH sensors and their corresponding measurement methods. Initially, the three different sensors, a conductometric PEDOT:PSS sensor, a voltammetric carbon-alizarin sensor and a potentiometric PANI sensor were selected based on certain established criteria and were reproduced on foils for a feasibility study. Mass but simple production, and feasibility for fabrication on textile substrates were also being the objectives of this work, and led to the deployment of printing and coating techniques for the sensor fabrication. These three sensors were printed on flexible foils and tested and verified for sensor performances. The performance measures like sensitivity, linearity and repeatability of the sensors and their mechanical properties were investigated with prime importance. Based on the experimental results together with a literature study, a conclusive comparison between the sensing principles with respect to device fabrication, functionality and wearability were performed. As per this analysis, one principle was chosen and further developed towards a textile-based printed sensor. A potentiometric graphene/PANI sensor was printed on a textile substrate and tested for a buffer solution of pH ranging from 4 to 10. The potentiometric sensor based on PANI shows a 45mV/pH sensitivity with linear sensor responses and repeatable characteristics. It proves as a potential pH sensor on textiles for wearable health applications.
- Condensed Matter Physics
- General Materials Science