Interface Engineering Assisted 3D Printing of Silicone Composites with Synergistically Optimized Impact Resistance and Electromagnetic Interference Shielding Effectiveness

Silicone composites have been universally employed in smart devices, flexible electronics, and mechanical metamaterials. However, it remained challenging to develop 3D printable silicone composites with desirable mechanical and electrical properties. Here, an interface engineering strategy is reported, developing heterointerfacial silver-coated hollow glass microspheres (SHGMs), which are integrated with polydimethylsiloxane (PDMS) for 3D printing of impact-resistant, highly conductive, and mechanically robust SHGMs-PDMS (SHP) composites. SHP simultaneously achieves high compression modulus (12.65 MPa), substantial energy dissipation density (1.58 × 10⁶ N m^-2 at 50% strain), excellent conductivity (2.55 × 10³ S m^-1), and long-period robustness. SHP presents extraordinary impact resistance under dynamic impacts, reaching a considerable energy dissipation of 1.91 kJ m^-1 at an incident velocity of 192.3 m s^-1. More importantly, SHP with 2 mm in thickness achieves an ultraefficient electromagnetic interference (EMI) effectiveness of 92.5 dB, which is among that of state-of-the-art silicone and its derivatives, and can maintain favorable shielding efficiency (>70 dB) after undergoing mechanical excitations. Moreover, the formability enables it to fabricate delicate structures with a negative Poisson's ratio, ensuring adaptive fit and thus providing complete protection for individuals. This work paves an effective way to rapidly manufacture silicone composites with expected functions for new-generation protective devices.