title: Wearable tactile sensor based on flexible microfluidics.
abstract: In this work, we develop a liquid-based thin film microfluidic tactile sensor of high flexibility, robustness and sensitivity. The microfluidic elastomeric structure comprises a pressure sensitive region and parallel arcs that interface with screen-printed electrodes. The microfluidic sensor is functionalized with a highly conductive metallic liquid, eutectic gallium indium (eGaIn). Microdeformation on the pressure sensor results in fluid displacement which corresponds to a change in electrical resistance. By emulating parallel electrical circuitry in our microchannel design, we reduced the overall electrical resistance of the sensor, therefore enhancing its device sensitivity. Correspondingly, we report a device workable within a range of 4 to 100 kPa and sensitivity of up to 0.05 kPa(-1). We further demonstrate its robustness in withstanding >2500 repeated loading and unloading cycles. Finally, as a proof of concept, we demonstrate that the sensors may be multiplexed to detect forces at multiple regions of the hand. In particular, our sensors registered unique electronic signatures in object grasping, which could provide better assessment of finger dexterity.
authors.affiliation: Singapore Institute of Manufacturing Technology, A*STAR, 138634 Singapore and Department of Biomedical Engineering, National University of Singapore, 117575 Singapore and Mechanobiology Institute, National University of Singapore, 117411 Singapore. ctlim@nus.edu.sg.
authors.forename: Joo Chuan
authors.initials: JC
authors.lastname: Yeo
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, 117575 Singapore.
authors.forename: Jiahao
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, 117575 Singapore.
authors.forename: Zhao Ming
authors.initials: ZM
authors.lastname: Koh
authors.affiliation: Singapore Institute of Manufacturing Technology, A*STAR, 138634 Singapore.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, 117575 Singapore and Mechanobiology Institute, National University of Singapore, 117411 Singapore. ctlim@nus.edu.sg.
authors.forename: Chwee Teck
authors.initials: CT
authors.lastname: Lim
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004548:Elasticity; D020724:Elastomers; D017097:Electric Impedance; D004867:Equipment Design; D005708:Gallium / Q000737:chemistry; D006225:Hand; D018737:Hand Strength; D006801:Humans; D007204:Indium / Q000737:chemistry; D008839:Microelectrodes; D044085:Microfluidics / Q000295:instrumentation*; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D011093:Polyethylene Terephthalates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011312:Pressure; D000075082:Proof of Concept Study; D015203:Reproducibility of Results; D012408:Rubber / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D000076251:Wearable Electronic Devices
chemical_list: D020724:Elastomers; D011093:Polyethylene Terephthalates; D011108:Polymers; C036925:elastomeric polymer; D007204:Indium; D012834:Silver; D012408:Rubber; D005708:Gallium