Influence of print settings on conductivity of 3D printed elastomers with carbon-based fillers

Abstract

Flexible, elastomeric materials for 3D printing have attracted considerable interest due to their potential application in clothing, shoe manufacturing and orthopedics. At the same time, smart clothing is also moving closer to more mainstream applications; as such, it is of considerable interest to combine both the structural and smart functions 3D printing offers in one material. While smart functionalities may be incorporated in a textile in a variety of ways (e.g. using shape-memory polymers), the use of electronic components such as sensors and actuators allow smart response to a multitude of stimuli. This necessitates the use of conductive and flexible materials that offer reliable conductivity after printing and provide optically attractive results. It is known that print conditions influence electrical properties, but while the print parameters are well researched for hard materials, there is not as much research for flexible compounds. Here, we show the influence of print speed, temperature, infill orientation, layer thickness and print mode (i.e. time between printing of successive layers). It was found that the most influential parameters are print mode, infill orientation and print temperature. The differences in electrical properties between the three materials used in this test may be explained by differences in filler content. A preliminary study into the optimization of the shape of a printed conductive line on elastic textile shows that the overall length of the printed path needs to be adapted to the maximum stretch of the textile, while shape has little influence on conductivity.