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Abstract Conductive adhesives are required for the integration of dissimilar material components to create soft electronic and robotic systems. Here, a heterogeneous liquid metal‐based conductive adhesive is developed that reversibly attaches to diverse surfaces with high stretchability (>100% strain), low modulus (<100 kPa), and strain‐invariant electrical conductivity. This SofT integrated composite with tacK through liquid metal (STICK‐LM) adhesive consists of a heterogeneous graded film with a liquid metal‐rich side that is embossed at prescribed locations for electrical conductivity and an electrically insulating adhesive side for integration. Adhesion behavior is tuned for adhesion energies > 70 Jm−2(≈ 25x enhancement over unmodified composites) and described with a viscoelastic analysis, providing design guidelines for controllable yet reversible adhesion in electrically conductive systems. The architecture of STICK‐LM adhesives provides anisotropic and heterogeneous electrical conductivity and enables direct integration into soft functional systems. This is demonstrated with deformable fuses for robotic joints, repositionable electronics that rapidly attach on curvilinear surfaces, and stretchable adhesive conductors with nearly constant electrical resistance. This study provides a methodology for electrically conductive, reversible adhesives for electrical and mechanical integration of multicomponent systems in emerging technologies.
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Liquid Metal‐Vitrimer Conductive Composite for Recyclable and Resilient Electronics
Abstract Electronic devices are ubiquitous in modern society, yet their poor recycling rates contribute to substantial economic losses and worsening environmental impacts from electronic waste (E‐waste) disposal. Here, recyclable and healable electronics are reported through a vitrimer‐liquid metal (LM) microdroplet composite. These electrically conductive, yet plastic‐like composites display mechanical qualities of rigid thermosets and recyclability through a dynamic covalent polymer network. The composite exhibits a high glass transition temperature, good solvent resistance, high electrical conductivity, and recyclability. The vitrimer synthesis proceeds without the need for a catalyst or a high curing temperature, which enables facile fabrication of the composite materials. The as‐synthesized vitrimer exhibits a fast relaxation time with reconfigurability and shape memory. The electrically conductive composite exhibits high electrical conductivity with LM volume loading as low as 5 vol.%. This enables the fabrication of fully vitrimer‐based circuit boards consisting of sensors and indicator LEDs integrated with LM‐vitrimer conductive wiring. Electrical self‐healing and thermally triggered material healing are further demonstrated with the composites. The vitrimer and LM‐composite provide a pathway toward fully recyclable, mechanically robust, and reconfigurable electronics, thus advancing the field of electronic materials.
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- Award ID(s):
- 2238754
- PAR ID:
- 10596103
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 37
- Issue:
- 37
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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