New solvent system for the improved electrochemical performance of screen-printed polyurethane membrane-based solid-state sensors

In our previous work aimed at mass producing chemical sensors, we have used the fabrication techniques of semiconductor processing and screen printing. In that work, we showed that high boiling-point solvents (i.e., low evaporation rates) were needed to increase the membrane paste viscosity and thixotropy [1]. While this approach achieved a paste with good mechanical properties for screen printing, the resulting sensors for some ions exhibited poor electrochemical performance in terms of detection limits and slopes. This paper reports a new technique using a low boiling-point plasticizer, dimethyl phthalate (DMP), to control viscosity in the membrane paste. Use of the plasticizer facilitates screen printing, while maintaining good electrochemical characteristics.