| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 740605 | Sensors and Actuators A: Physical | 2006 | 8 Pages |
Miniature sensors, which are rugged and reliable in nature, are essential to meet the growing demand for environmental and biomedical monitoring systems. Developing such sensors using screen-printing and drop coating techniques allows the combination of two cost effective and flexible technologies. Using this approach, a wide variety of materials could be combined to produce sensors with the desired physical properties. Silver electrodes were screen-printed onto alumina substrates, while polymer/carbon-black composites based on polyvinyl butyral, polyvinyl acetate and polystyrene were deposited by drop coating. The addition of surfactant resulted in a more even dispersion of carbon-black throughout the composites, which was observed by TEM. The frequency dependence of the composites also confirmed this result. Pressure was applied using a Lloyd Instruments LR50k in the range 0–2500 kPa and the sensitivity was taken to be the slope of the graph. It was found that the materials displayed a high sensitivity to pressure with good repeatability. Detailed studies of the composites temperature dependency showed that each material has a negative temperature coefficient and were particularly sensitive when the temperature was brought below room temperature. This was improved by coating the sample surface.
