Piezoresistive chemical sensors based on hydrogels

Margarita Guenther; Gerald Gerlach; Thomas Wallmersperger

doi:10.1117/12.821335

18 May 2009 Piezoresistive chemical sensors based on hydrogels

Margarita Guenther, Gerald Gerlach, Thomas Wallmersperger

Proceedings Volume 7362, Smart Sensors, Actuators, and MEMS IV; 736218 (2009) https://doi.org/10.1117/12.821335
Event: SPIE Europe Microtechnologies for the New Millennium, 2009, Dresden, Germany

Abstract

Already eight years ago, the usage of piezoresistive sensors for chemical measurands was proposed at the Solid State Electronics Laboratory of the Dresden University of Technology ^[1]. Adding functionalised polymer coating which shows swelling due to chemical or biological values leads to a similar deflection of the thin silicon bending plate like for pressure sensors. The application of "stimuli-responsive" or "smart" cross-linked gels in chemical sensors is based on their ability to a phase transition under the influence of external excitations (pH, concentration of additives in water, temperature). Combining a "smart" hydrogel and a micro fabricated pressure sensor chip allows to continuously monitor the analytedependent swelling of a hydrogel and hence the analyte concentration in ambient aqueous solutions. The sensitivity of hydrogels with regard to the concentration of such additives as H⁺-ions (pH sensor), transition-metal ions, salts, organic solvents and proteins in water was investigated. It has been demonstrated that the sensor's sensitivity depends on the polymer composition as well as on the polymer cross-linking degree. Time constants down to a few ten seconds have been found for thin hydrogel films deposited directly on the backside of the silicon bending plate. In order to achieve an optimum between sensor signal amplitude and sensor response time, the gel swelling/deswelling kinetics was investigated. Some methods improving the properties of the chemical sensors have been proposed. The long-term measurements have shown that the lifetime of piezoresistive chemical sensors can be prolonged up to several years provided that specific operation and storage conditions are fulfilled.

Citation Download Citation

Margarita Guenther, Gerald Gerlach, and Thomas Wallmersperger "Piezoresistive chemical sensors based on hydrogels", Proc. SPIE 7362, Smart Sensors, Actuators, and MEMS IV, 736218 (18 May 2009); https://doi.org/10.1117/12.821335

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available