title: Interfacing liquid metals with stretchable metal conductors.
abstract: Highly stretchable conductors are essential components in deformable electronics. Owing to their high stretchability and conductivity, liquid metals have attracted significant attention for use as circuits and interconnections. However, their poor wettability to stretchable metal electrodes prevents the formation of stable electrical connections. This study examined two approaches for creating a stable interface between a liquid metal (EGaIn) and stretchable metal electrodes via: (i) the use of honeycomb-structured stretchable metal electrodes and (ii) the addition of a conducting polymer interlayer. The line width of the honeycomb had a significant influence on the formation of a stable interface. The liquid metal formed a stable film layer on honeycomb metal electrodes, which have line widths of less than 50 μm. Coating
  PSS with a nonionic surfactant lowered the interfacial energy of EGaIn with flat stretchable metal surfaces; hence EGaIn was coated uniformly on the stretchable metal surfaces. Strain sensors were fabricated as a demonstrative example of an application that utilizes the stable interface.
authors.affiliation: †Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-Ro, Seodaemun-Gu, Seoul, Korea 120-749.
authors.forename: Bongsoo
authors.initials: B
authors.lastname: Kim
authors.affiliation: †Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-Ro, Seodaemun-Gu, Seoul, Korea 120-749.
authors.forename: Jaehyeok
authors.initials: J
authors.lastname: Jang
authors.affiliation: ‡Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk Korea 790-784.
authors.forename: Insang
authors.initials: I
authors.lastname: You
authors.affiliation: †Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-Ro, Seodaemun-Gu, Seoul, Korea 120-749.
authors.forename: Jaeyoon
authors.initials: J
authors.lastname: Park
authors.affiliation: ‡Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk Korea 790-784.
authors.forename: SangBaie
authors.initials: S
authors.lastname: Shin
authors.affiliation: §National Creative Research Initiative Center for Smart Block Copolymers, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk Korea 790-784.
authors.forename: Gumhye
authors.initials: G
authors.lastname: Jeon
authors.affiliation: §National Creative Research Initiative Center for Smart Block Copolymers, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk Korea 790-784.
authors.forename: Jin Kon
authors.initials: JK
authors.lastname: Kim
authors.affiliation: ‡Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk Korea 790-784.
authors.forename: Unyong
authors.initials: U
authors.lastname: Jeong
keywords: EGaIn; interface; liquid metal; strain sensor; stretchable conductor; wettability