Marios Sophocleous

An investigation into the effect of fabrication parameter variation on the characteristics of screen‐printed thick‐film silver/silver chloride reference electrodes

Purpose – The purpose of this paper is to show how the fabrication parameters of screen‐printed thick‐film reference electrodes have been experimentally varied and their effect on device characteristics investigated.Design/methodology/approach – The tested devices were fabricated as screen‐printed planar structures consisting of a silver back contact, a silver/silver chloride interfacial layer and a final salt reservoir layer containing potassium chloride. The fabrication parameters varied included deposition method and thickness, salt concentration and binder type used for the final salt reservoir layer. Characterisation was achieved by monitoring the electrode potentials as a function of time following initial immersion in test fluids in order to ascertain initial hydration times, subsequent electrode drift rates and useful lifetime of the electrodes. Additionally, the effect of fabrication parameter variation on electrode stability and their response time in various test media was also investigated.Fin...

Thick film screen printed environmental and chemical sensor array reference electrodes suitable for subterranean and subaqueous deployments

Purpose – The purpose of this paper is to report thick film environmental and chemical sensor arrays designed for deployment in both subterranean and submerged aqueous applications.Design/methodology/approach – Various choices of materials for reference electrodes employed in these different applications have been evaluated and the responses of the different sensor types are compared and discussed.Findings – Results indicate that the choice of binder materials is critical to the production of sensors capable of medium term deployment (e.g. several days) as the binders not only affect the tradeoff between hydration time and drift but also have a significant bearing on device sensitivity and stability. Sensor calibration is shown to remain an issue with long‐term deployments (e.g. several weeks) but this can be ameliorated in the medium term with the use of novel device fabrication and packaging techniques.Originality/value – The reported results indicate that is possible through careful choice of materials...

An experimental analysis of Thick-Film solid-state reference electrodes

Thick-Film planar solid-state Silver/Silver Chloride (Ag/AgCl) reference electrodes were developed and tested for ion susceptibility and long term drift in approximately 0.04 M potassium chloride (KCl) solution. Various types of electrodes were tested exhibiting stabilities down to 2 millivolts per decade change of chloride concentration. It is demonstrated that Thick-Film reference electrodes are suitable for use in underground soil measurements due to their ruggedness and robustness.

A novel thick-film screen printed electrical conductivity sensor for measurement of liquid and soil conductivity

Results are reported from an initial evaluation of a novel conductivity sensor that has been incorporated onto a multi-element thick film sensor array designed for soil and water analysis. The new sensor exhibits a more repeatable cell constant of approximately 0.15 cm-1 over a wider range of conductivities compared with conductivity sensor designs previously employed in the sensor array. The new sensor is currently performing very well in an investigation of soil structural properties where its output is being correlated with soil water content in a study of different soil porosities.