A Novel pH Sensor Based on the Swelling of A Hydrogel Membrane

Abstract

A novel pH sensor consists of the pH sensitive hydrogel and conductive polymer layer was developed. The monomers of hydroxyl ethyl methacrylate were polymerized and modified by UV radiation to become the pH sensitive hydrogel. The pH sensitive functional group of poly(HEMA) was created by UV treatment. The sensing principle of the device was based on the piezoresistive effect induced by the swelling behavior of the hydrogel varied with pH value of testing solution on the conductive polymer. The correlation between the sensitivity of the device and UV radiation dosages was investigated. The stree-strain relationship of the polymer membranes and output characteristic of pH sensor were measured, and the computer-aid analysis based on the hyperelastic- viscous model of hydrogel was achieved by using the fine element method. The optimization aspect of pH sensor also was found from the simulating process. © International Federation of Medical and Biological Engineering 2009.