Root-inspired, template-confined additive printing for fabricating high-robust conformal electronics

Conformal electronic devices on freeform surface play a critical role in the emerging smart robotics, smart skins, and integrated sensing systems. However, their functional structures such as circuits tend to tear-off, break, or crack under mechanical or thermal influence when in service, thus limiting the application reliability of conformal electronics. Herein, inspired by the tree root system, template-confined additive (TCA) printing technology was presented for reliable fabrication of robust circuits. TCA printing technology involves the penetration of adhesive into the functional material, thereby enhancing the mechanical robustness of the circuits, allowing them to maintain their electrical performance despite the presence of external damaging factors such as scratching, abrasion, folding, and high temperatures. For example, herein, the circuits could withstand mechanical abrasion at temperatures as high as 350 °C without compromising electrical properties. Benefiting from the confines of template, the printed circuits achieved resolutions of up to 300 nm, suitable for various materials such as P(VDF-TrFE), MWCNTs, and AgNPs, which enabled the multi-material self-aligned fabrication. Furthermore, the versatility of TCA printing was presented by fabricating circuits on arbitrary substrates, and realizing various devices, such as conformal temperature/humidity sensing system and epidermal ultra-thin energy storage system. These applications present the significant potential of TCA printing in fabricating intelligent devices.