Free swelling and confined smart hydrogels for applications in chemomechanical sensors for physiological monitoring

SENSORS AND ACTUATORS B-CHEMICAL

卷:136

Article

Lin, G.¹  Chang, S.¹  Kuo, C. -H.¹  Magda, J.¹  Solzbacher, F.^1,2,3 

[1] Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA

[2] Univ Utah, Dept Elect & Comp Engn, Salt Lake City, UT 84112 USA

[3] Univ Utah, Dept Bioengn, Salt Lake City, UT 84112 USA

关键词: Chemical sensor;    Hydrogel;    Piezoresistive sensor;    Smart material;   

DOI  :  10.1016/j.snb.2008.11.001

来源: Elsevier

【 摘 要 】

We investigate thin films of smart polymer hydrogels used to convert miniature pressure sensors into novel chemomechanical sensors. In this versatile sensing approach, a smart hydrogel is confined between a porous membrane and the diaphragm of a piezoresistive pressure transducer. An increase in the environmental analyte concentration, as sensed through the pores of the membrane, is detected by measuring the change in pressure exerted by the hydrogel on the pressure transducer diaphragm. We compare the response of such a sensor with the response of a free-swelling hydrogel identical to the one used within the sensor. The sensor and the free hydrogel are observed to have comparable mean response times. However, the time-dependent response curve of the sensor, unlike that of the free hydrogel, is highly asymmetric between swelling and deswelling, with a smaller time constant for deswelling. We also investigate novel methods for increasing sensor sensitivity, such as use of a two-layer membrane with a nanoporous polymer inner layer. and pre-loading of the hydrogel under pressure. In ionic strength response tests, use of an inner membrane increases sensor sensitivity without increasing mean response time, an effect that varies with membrane water fraction. (C) 2008 Elsevier B.V. All rights reserved.

【 授权许可】

Free