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Liquid Metal Droplet and Graphene Co‐Fillers for Electrically Conductive Flexible Composites
Author(s) -
Saborio Maricruz G.,
Cai Shengxiang,
Tang Jianbo,
Ghasemian Mohammad B.,
Mayyas Mohannad,
Han Jialuo,
Christoe Michael J.,
Peng Shuhua,
Koshy Pramod,
Esrafilzadeh Dorna,
Jalili Rouhollah,
Wang Chun H.,
KalantarZadeh Kourosh
Publication year - 2020
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201903753
Subject(s) - materials science , composite material , electrical conductor , graphene , composite number , electrical resistivity and conductivity , electrically conductive , liquid metal , flexible electronics , nanocomposite , nanotechnology , engineering , electrical engineering
Colloidal liquid metal alloys of gallium, with melting points below room temperature, are potential candidates for creating electrically conductive and flexible composites. However, inclusion of liquid metal micro‐ and nanodroplets into soft polymeric matrices requires a harsh auxiliary mechanical pressing to rupture the droplets to establish continuous pathways for high electrical conductivity. However, such a destructive strategy reduces the integrity of the composites. Here, this problem is solved by incorporating small loading of nonfunctionalized graphene flakes into the composites. The flakes introduce cavities that are filled with liquid metal after only relatively mild press‐rolling (<0.1 MPa) to form electrically conductive continuous pathways within the polymeric matrix, while maintaining the integrity and flexibility of the composites. The composites are characterized to show that even very low graphene loadings (≈0.6 wt%) can achieve high electrical conductivity. The electrical conductance remains nearly constant, with changes less than 0.5%, even under a relatively high applied pressure of >30 kPa. The composites are used for forming flexible electrically‐conductive tracks in electronic circuits with a self‐healing property. The demonstrated application of co‐fillers, together with liquid metal droplets, can be used for establishing electrically‐conductive printable‐composite tracks for future large‐area flexible electronics.