This paper reports soft and stretchable films of liquid metal particles (LMPs) that offer high surface area and high conductivity. Liquid metals (LM) based on gallium are compelling conductors for soft and stretchable devices, yet it is difficult to make electrodes of LM with high surface area due to the tendency of liquids to minimize their surface area. To form films of percolated particles with high surface area, LMPs are first created by sonicating LM in isopropanol with trace amounts of hydrochloric acid and 1,6‐hexane dithiol to decrease the amount of surface oxide on the LMPs. A film of these particles placed on a tacky substrate is initially insulating but percolate into conductive paths by straining the substrate. The resulting electrode has high conductivity (1.64 × 105S m−1) and high surface area (1257% greater than a bulk LM film with the same areal footprint). Interestingly, these electrodes have nearly strain‐invariant resistance (
As stretchable devices become well established for applications in soft robotics and wearable devices, the compliant conductors that make these applications possible must also be reliable and survive for the entire device lifetime. Liquid metals such as Galinstan are a potential solution as non‐toxic, stretchable, and low‐resistance conductors. Rigorous investigations of liquid metal lifetimes, however, are limited. This work presents the median lifetime of liquid metal‐filled silicone tubes under current density on the order of 1 kAcm−2, which is necessary for applications such as electromagnetic actuators. In these conductors, the median lifetime increases by a factor of over 4700 as current decreases from 2 to 1 kAcm−2. By cooling the sample, median failure time increases from 112 s to 9.4 h, which suggests straightforward solutions to maximize liquid metal wire lifetime by increasing thermal conductivity or by duty cycling the applied current.
more » « less- Award ID(s):
- 1846954
- NSF-PAR ID:
- 10451997
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- Volume:
- 6
- Issue:
- 4
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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