Numerical and experimental analyses of the crack propagation in nanocomposite thin-films by using dynamic particle difference methods

Abstract

Nanocomposites composed of an organic semiconductor and an elastomer exhibit a stable electrical performance and high mechanical durability, and can thus facilitate the development of stretchable electronic devices. However, the inadequate extent of research on the mechanical behaviors of these nanocomposites limits the application scope of such materials. Identifying and clarifying the crack propagation mechanisms is essential to improve the performance and durability of electronic devices. Therefore, this study examined the crack propagation behaviors of homogeneous nanocomposite materials through numerical simulations and experimental analyses. Nanocomposite thin-film samples for the tensile strength test were manufactured by mixing an organic semiconductor poly(3-hexylthiophene) and a styrene-butadiene-styrene (SBS) elastomer in a nanocomposite format. The samples with initial cracks were subjected to pseudo-free-standing tensile tests to observe the crack propagation and stress-strain behaviors under given experimental conditions. Furthermore, the dynamic particle difference method (PDM) was used to numerically analyze the crack propagation properties of the nanocomposites in two-dimension. The PDM is more effective than the finite element method in analyzing the crack propagation, considering that nodes can be freely created and eliminated in every time step. As a result, the initial crack angle for the set problem was changed to 21, 14, and 19 degrees with respect to the mixing concentration of SBS (0.0, 0.15, and 0.3 wt%). The numerical simulation by the PDM and experimental results was almost the same. This demonstrates that the proposed numerical technique can predict the experimentally measured fracture behavior of nanocomposites.