Numerical and Analytical Modeling to Determine Performance Trade-offs in Hydrogel-based pH Sensors

Piyush Dak, Purdue University
Muhammad Ashraful Alam, Purdue University

Date of this Version



The article is published in IEEE TED:

"Numerical and Analytical Modeling to Determine Performance Trade-offs in Hydrogel based pH Sensors", P. Dak and M. A. Alam, IEEE Transactions on Electron Devices, 63, 6 (2016)"

The uploaded version is the final accepted version for which the authors hold the copyright.


Hydrogel based pH sensors are promising candidates for implantable sensors due to their low-cost and biocompatibility. Despite their commercial potential and numerous theoretical/experimental reports, the trade-offs between different performance parameters are not well understood, and explicitly stated. In this work, we develop a numerical and analytical framework to show that there is a fundamental trade-off between the performance parameters i.e. sensitivity/dynamic range vs. response-time/response-asymmetry in hydrogel sensors under constrained swelling conditions. Specifically, we consider the effect of the gel parameters, such as the ionizable group density ( Nf) and its dissociation constant ( Ka), on the sensor performance. We show that improvement of sensitivity/dynamic range leads to degradation in response time/symmetry and therefore, a compromise must be made to optimize device performance.


Biomedical | Electrical and Electronics | Electronic Devices and Semiconductor Manufacturing