Effect of Polyethylene Glycol in Porous Alumina Based
Thin Film Capacitive Humidity Sensor and Its Modelling |
Tarikul Islam*, Lokesh Kumar and Geetika Aswani1
pages 47-51
DOI:10.1080/0371750X.2013.793995 |
Abstract |
Present work deals with the development of a capacitive humidity sensor using porous thin film of aluminium
oxide on the interdigitated gold electrodes. We describe the effect of polyethylene glycol (PEG) addition to pure sol
solution of -Al2O3 on the humidity sensing characteristics of the sensor. The film was fabricated by dip coating of
sol solution obtained from the sol-gel method. To compare the response characteristics, three different sensors
such as pure alumina sol, 0.125 g and 1 g PEG added in pure sol have been fabricated. The electrical parameters of
the sensor have been determined by Agilent 4294A impedance analyzer. The sensor so obtained was found to be
sensitive in humidity range of 1 to 90%. Addition of fixed amount of PEG in pure alumina sol improved the response
characteristics significantly. The response time of the 0.125 g PEG added sensor was very low, about 10 s and the
recovery time was about 3 s. The behaviour of the most sensitive sensor has been modelled with a view to minimize
the error and was fitted well with the experimental data.
[Keywords: Porous alumina, Sol-gel method, Effect of PEG, Pore morphology, Capacitive sensor, Dip coating] |
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