title: Ultrasensitive mechanical crack-based sensor inspired by the spider sensory system.
abstract: Recently developed flexible mechanosensors based on inorganic silicon, organic semiconductors, carbon nanotubes, graphene platelets, pressure-sensitive rubber and self-powered devices are highly sensitive and can be applied to human skin. However, the development of a multifunctional sensor satisfying the requirements of ultrahigh mechanosensitivity, flexibility and durability remains a challenge. In nature, spiders sense extremely small variations in mechanical stress using crack-shaped slit organs near their leg joints. Here we demonstrate that sensors based on nanoscale crack junctions and inspired by the geometry of a spider's slit organ can attain ultrahigh sensitivity and serve multiple purposes. The sensors are sensitive to strain (with a gauge factor of over 2,000 in the 0-2 per cent strain range) and vibration (with the ability to detect amplitudes of approximately 10 nanometres). The device is reversible, reproducible, durable and mechanically flexible, and can thus be easily mounted on human skin as an electronic multipixel array. The ultrahigh mechanosensitivity is attributed to the disconnection-reconnection process undergone by the zip-like nanoscale crack junctions under strain or vibration. The proposed theoretical model is consistent with experimental data that we report here. We also demonstrate that sensors based on nanoscale crack junctions are applicable to highly selective speech pattern recognition and the detection of physiological signals. The nanoscale crack junction-based sensory system could be useful in diverse applications requiring ultrahigh displacement sensitivity.
authors.affiliation: 1] Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea [2] Division of WCU Multiscale Mechanical Design, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Daeshik
authors.initials: D
authors.lastname: Kang
authors.affiliation: Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Peter V
authors.initials: PV
authors.lastname: Pikhitsa
authors.affiliation: Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Yong Whan
authors.initials: YW
authors.lastname: Choi
authors.affiliation: Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Chanseok
authors.initials: C
authors.lastname: Lee
authors.affiliation: Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Sung Soo
authors.initials: SS
authors.lastname: Shin
authors.affiliation: Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Linfeng
authors.initials: L
authors.lastname: Piao
authors.affiliation: 1] Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 440-746, South Korea [2] School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 440-746, South Korea.
authors.forename: Byeonghak
authors.initials: B
authors.lastname: Park
authors.affiliation: 1] Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea [2] Division of WCU Multiscale Mechanical Design, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea [3] Interdisciplinary Program of Bioengineering, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Kahp-Yang
authors.initials: KY
authors.lastname: Suh
authors.affiliation: 1] Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 440-746, South Korea [2] School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 440-746, South Korea.
authors.forename: Tae-il
authors.initials: TI
authors.lastname: Kim
authors.affiliation: 1] Global Frontier Center for Multiscale Energy Systems, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea [2] Division of WCU Multiscale Mechanical Design, Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Mansoo
authors.initials: M
authors.lastname: Choi
mesh_terms: D000818:Animals; D032701:Biomimetics / Q000379:methods*; D006801:Humans; D040542:Mechanotransduction, Cellular / Q000502:physiology; D009068:Movement; D009146:Music; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D010984:Platinum / Q000737:chemistry; D018583:Pliability; D011312:Pressure; D012867:Skin; D013016:Sound; D013060:Speech; D013112:Spiders / Q000033:anatomy & histology / Q000502:physiology*; D014732:Vibration; D014921:Wings, Animal / Q000502:physiology
chemical_list: D010984:Platinum