Inkjet printing technology for polymer thermal conductivity measurement by the three omega method

The three omega method has proven ability to accurately measure the thermal conductivity of solid and soft materials. Nevertheless, in the case of soft materials, the application of the three omega method is still challenging because up to now it generally requires techniques that are time consuming and costly, such as lithography. In this paper, we present an alternative for this kind of material based on inkjet printing technology. To evaluate the performance of this technique, polyimide samples have been prepared by photolithography and inkjet printing. We show that the thermal conductivities measured in both cases by means of the 3ω method are very close; demonstrating that inkjet printing technology is a good candidate for characterization of flexible materials in terms of thermal conductivity. Besides the experimental study, a theoretical investigation based on an analytical approach, namely Cahill's method, and a numerical method based on a FEM tool is proposed.