The impact of carbon content and mesh on the characteristics of screen printed conductive structures

Purpose - The purpose of this paper is to carry out a comprehensive experimental investigation into the role of screen and conductive carbon material formulation on line conductivity and printing capability in the screen printing process, to provide design knowledge and further understanding of the screen printing for printed carbon. Design/methodology/approach - A full factorial experiment was carried out where six carbon materials were printed through ten screens to a polyester substrate under a set of standard conditions. Findings - Material characterization showed that viscosity and the corresponding viscous and elastic material modulli increased with solids content and that the elastic properties at low shear are significant. The solids carbon content materials were unable to produce the minimum printable line features possible with the low carbon materials. Increasing the solids contents reduced the final cured line resistance, reduced the printed line width, increased the film thickness, increased the cross sectional area and reduced the material resistivity. Material resistivities were around 700 to 950 mu Omega cnn were obtained in the printed lines. Research limitations/implications - Lower material resistivities were obtained with higher solids materials and it is postulated that the increased visco-elastic nature of the solids content materials, play a role in determining the microscopic structure of the cured film through alignment of the carbon graphite platelets. Practical implications - A dataset which allows material, screen and print characteristics has been created allowing process optimization and formulation development to be accelerated. Originality/value - The work provides insight into the role of material properties and process settings on the electrical and physical characteristics of printed carbon.