Structured Interfaces for Improving the Tensile Strength and Toughness of Stiff/Highly Stretchable Polymer Hybrids

The stiff/highly stretchable polymer hybrids have a broad field of applications including robotics, electronic devices, and biomedical devices. However, poor interfacial bonding between chemically dissimilar polymers makes it difficult to achieve reliable structural performance. Building a robust interface within the polymer hybrids is one of the most important concerns. Here, the structured interface with different geometrical waveform patterns, including zigzag, buzzsaw, and strip shape is investigated for their effectiveness in improving mechanical properties of the interface. The enhancement effects of different geometries of the structured interfaces on both the tensile strength and tensile toughness are characterized by uniaxial tension tests. The finite element analysis simulations of the interface are implemented to investigate the enhancement mechanism, considering both the material nonlinearity under large deformation and the geometric nonlinearity derived from the high asymmetry in the interfacial configuration. Both the interfacial geometry and the intrinsic adhesive property of materials influence the load transfer mechanism at the interface and consequently determine the failure modes. Optimal geometrical designs of the interfacial geometries are proposed to achieve the best interfacial enhancement. The present study may provide guidance for designing the interfacial geometries in the polymer hybrids.