Microtensile testing of submicrometer thick functional polymer samples

Organic electronic devices are currently being introduced in commercial applications such as flexible displays. Due to the mechanical loading of these devices during bending, it is important to know the mechanical properties in order to assess reliability. It is therefore essential to develop experimental setups for the mechanical characterization of submicrometer thick functional polymer layers. In this paper a new microtensile approach is presented along with first results for Young's modulus of polyimide (PI) and the conductive polymer PEDOT:PSS obtained using this method. The microtensile specimen are made of a bilayer consisting of PI as the substrate layer and of a submicron layer of PEDOT:PSS deposited on top of it. The mechanical properties are derived from comparison of measurements performed on samples with and without the functional layer and by varying this layer's thickness. A thorough error analysis is also presented to provide an overview of the precision inherent in this approach. The experiments yield Young's moduli of 3.28 ± 0.34 GPa for PI and of 4.51 ± 0.34 GPa for PEDOT:PSS.