Development and Characterization of a Novel Low-Cost Water-Level and Water Quality Monitoring Sensor by Using Enhanced Screen Printing Technology with PEDOT:PSS.

Bei Wang,Klaus-Dieter Lang,Martin Schneider-Ramelow,Moritz Hubl,Markus Woehrmann,Katharina Becker,Manuel Baeuscher,Piotr Mackowiak,Nils Juergensen,Xiaodong Hu,Ha-Duong Ngo

doi:10.3390/mi11050474

Abstract

A novel capacitive sensor for measuring the water-level and monitoring the water quality has been developed in this work by using an enhanced screen printing technology. A commonly used environment-friendly conductive polymer poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) for conductive sensors has a limited conductivity due to its high sheet resistance. A physical treatment performed during the printing process has reduced the sheet resistance of printed PEDOT:PSS on polyethylenterephthalat (PET) substrate from 264.39 Ω/sq to 23.44 Ω/sq. The adhesion bonding force between printed PEDOT:PSS and the substrate PET is increased by using chemical treatment and tested using a newly designed adhesive peeling force test. Using the economical conductive ink PEDOT:PSS with this new physical treatment, our capacitive sensors are cost-efficient and have a sensitivity of up to 1.25 pF/mm.

Highlights

Sensors and microsystems appear widely in different areas, especially in this explosively growing digitalization era
A novel capacitive sensor for measuring the water-level and monitoring the water quality has been developed in this work by using an enhanced screen printing technology
These results indicate that our chemical treatment largely enhanced the bonding rate of hydrogen bonds. This enhanced boding rate is related to the increase in free hydroxyl and carboxyl groups on the chemical-treated substrate surface. These results show that the bonding became strong enough for making PEDOT:PSS printed sensors on PET substrate more reliable

Summary

Introduction

Sensors and microsystems appear widely in different areas, especially in this explosively growing digitalization era. The new generation of sensors and microsystems focus more on environment-friendly, flexible, and cost-efficient materials and processes, such as conductive polymers and flexible devices [1,2,3]. When the pollutants change the water quality, sensors can measure this change by detecting the surrounding electromagnetic field. Paczesny et al [4] reported a silver nanoparticle printed capacitive sensor by using inkjet printing technology, with a sensitivity of 0.074 pF/mm. The conductive material using silver nanoparticles has been proved highly toxic [6,7,8]. Even a small leak of silver nanoparticles from the printed sensor could pollute water sources seriously.

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Results

Conclusion