title: Microtopography-Guided Conductive Patterns of Liquid-Driven Graphene Nanoplatelet Networks for Stretchable and Skin-Conformal Sensor Array.
abstract: Flexible thin-film sensors have been developed for practical uses in invasive or noninvasive cost-effective healthcare devices, which requires high sensitivity, stretchability, biocompatibility, skin/organ-conformity, and often transparency. Graphene nanoplatelets can be spontaneously assembled into transparent and conductive ultrathin coatings on micropatterned surfaces or planar substrates via a convective Marangoni force in a highly controlled manner. Based on this versatile graphene assembled film preparation, a thin, stretchable and skin-conformal sensor array (144 pixels) is fabricated having microtopography-guided, graphene-based, conductive patterns embedded without any complicated processes. The electrically controlled sensor array for mapping spatial distributions (144 pixels) shows high sensitivity (maximum gauge factor ≈1697), skin-like stretchability (<48%), high cyclic stability or durability (over 105cycles), and the signal amplification (≈5.25 times) via structure-assisted intimate-contacts between the device and rough skin. Furthermore, given the thin-film programmable architecture and mechanical deformability of the sensor, a human skin-conformal sensor is demonstrated with a wireless transmitter for expeditious diagnosis of cardiovascular and cardiac illnesses, which is capable of monitoring various amplified pulse-waveforms and evolved into a mechanical/thermal-sensitive electric rubber-balloon and an electronic blood-vessel. The microtopography-guided and self-assembled conductive patterns offer highly promising methodology and tool for next-generation biomedical devices and various flexible/stretchable (wearable) devices.
authors.affiliation: School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.
authors.forename: Youngjin
authors.initials: Y
authors.lastname: Park
authors.affiliation: Department of Applied Chemistry, Dongduk Women's University, Seoul, 02748, Republic of Korea.
authors.forename: Jongwon
authors.initials: J
authors.lastname: Shim
authors.affiliation: SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.
authors.forename: Suyeon
authors.initials: S
authors.lastname: Jeong
authors.affiliation: School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.
authors.forename: Gi-Ra
authors.initials: GR
authors.lastname: Yi
authors.affiliation: School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.
authors.forename: Heeyeop
authors.initials: H
authors.lastname: Chae
authors.affiliation: School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.
authors.forename: Jong Wook
authors.initials: JW
authors.lastname: Bae
authors.affiliation: National Creative Research Initiative Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KI for the Nanocentury, KAIST, Daejeon, 34141, Republic of Korea.
authors.forename: Sang Ouk
authors.initials: SO
authors.lastname: Kim
authors.affiliation: School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.|SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.|Samsung Advanced Institute of Health Science & Technology, Sungkyunkwan University (SKKU), Suwon, 440-746, Republic of Korea.
authors.forename: Changhyun
authors.initials: C
authors.lastname: Pang
keywords: biosensors; conductive patterning; graphene nanoplatelets; self-assembly