Direct printing of flexible and stretchable conductors provides a low‐cost mask‐less approach for the fabrication of next‐generation electronics. In this work, an electrohydrodynamic (EHD) printing technology is studied to achieve high‐resolution printing of low‐melting‐point metal alloys, which enables low‐cost direct fabrication of metallic conductors with sub 50 µm resolution. The EHD printed microscale metallic conductors represent a promising way to create conductive paths with metallic conductivity and excellent flexibility and stretchability. A stable electrical response is achieved after hundreds of bending cycles and during stretching/releasing cycles in a large range of tensile strain (0–70%) for the printed conductors with properly designed 2D patterns. Due to the low melting point of the metal alloy ink, the printed conductor demonstrates self‐healing capability that recovers from failure simply by heating the device above the eutectic temperature of the metal ink and applying slight pressure. A high‐density touch sensor array is fabricated to demonstrate the high‐resolution capability of the EHD printing for the direction fabrication of flexible and stretchable devices.
Multi‐layer electrical interconnects are critical for the development of integrated soft wearable electronic systems, in which functional devices from different layers need to be connected together by vertical interconnects. In this work, electrohydrodynamic (EHD) printing technology is studied to achieve multi‐layer flexible and stretchable electronics by direct printing vertical interconnects as vertical interconnect accesses (VIAs) using a low‐melting‐point metal alloy. The EHD printed metallic vertical interconnection represents a promising way for the direct fabrication of multilayer integrated electronics with metallic conductivity and excellent flexibility and stretchability. By controlling the printing conditions, vertical interconnects that can bridge different heights can be fabricated. To achieve reliable VIA connections under bending and stretching conditions, an epoxy protective structure is printed around the VIA interconnects to form a core‐shell structure. A stable electrical response is achieved under hundreds of bending cycles and during stretching/releasing cycles in a large range of tensile strain (0–40%) for the printed conductors with VIA interconnects. A few multi‐layer devices, including a multiple layer heater, and a pressure‐based touch panel are fabricated to demonstrate the capability of the EHD printing for the direct fabrication of vertical metallic VIA interconnects for flexible and stretchable devices.
more » « less- Award ID(s):
- 1728370
- NSF-PAR ID:
- 10449733
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- Volume:
- 6
- Issue:
- 9
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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