Imperfection sensitivity of mechanical properties in soft network materials with horseshoe microstructures

Developments of soft network materials with rationally distributed wavy microstructures have enabled many promising applications in bio-integrated electronic devices, due to their abilities to reproduce precisely nonlinear mechanical properties of human tissues/organs. In practical applications, the soft network materials usually serve as the encapsulation layer and/or substrate of bio-integrated electronic devices, where deterministic holes can be utilized to accommodate hard chips, thereby increasing the filling ratio of the device system. Therefore, it is essential to understand how the hole-type imperfection affects the stretchability of soft network materials with various geometric constructions. This work presents a systematic investigation of the imperfection sensitivity of mechanical properties in soft network materials consisting of horseshoe microstructures, through combined computational and experimental studies. A factor of imperfection insensitivity of stretchability is introduced to quantify the influence of hole imperfections, as compared to the case of perfect soft network materials. Such factor is shown to have different dependences on the arc angle and normalized width of horseshoe microstructures for triangular network materials. The soft triangular and Kagome network materials, especially with the arc angle in the range of (30 $$^{\circ }$$ , 60 $$^{\circ }$$ ), are found to be much more imperfection insensitive than corresponding traditional lattice materials with straight microstructures. Differently, the soft honeycomb network materials are not as imperfection insensitive as traditional honeycomb lattice materials.