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Enhanced Sensitivity of Capacitive Pressure and Strain Sensor Based on CaCu 3 Ti 4 O 12 Wrapped Hybrid Sponge for Wearable Applications
Author(s) -
Chhetry Ashok,
Sharma Sudeep,
Yoon Hyosang,
Ko Seokgyu,
Park Jae Yeong
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201910020
Subject(s) - materials science , capacitive sensing , dissipation factor , dielectric , composite material , pressure sensor , permittivity , optoelectronics , nanotechnology , electrical engineering , engineering , physics , thermodynamics
Pressure sensors with highly sensitive and flexible characteristics have extensive applications in wearable electronics, soft robotics, human–machine interface, and more. Herein, an effective strategy is explored to enhance the sensitivity of the capacitive pressure sensor by fabricating a dielectric hybrid sponge consisting of calcium copper titanate (CaCu 3 Ti 4 O 12 , CCTO), a giant dielectric permittivity material, in polyurethane (PU). An ultrasoft CCTO@PU hybrid sponge is fabricated via dip‐coating the PU sponge into surface‐modified CCTO nanoparticles using 3‐aminopropyl triethoxysilane. The overall results show that the –NH 2 functionalized CCTO attributes proper adhesion of CCTO with the –OCN group of the PU to enhance interfacial polarization leading to a high dielectric permittivity (167.05) and low loss tangent (0.71) beneficial for flexible pressure sensing applications. Moreover, the as‐prepared CCTO@PU hybrid sponge at 30 wt% CCTO concentration exhibits excellent electromechanical properties with an ultralow compression modulus of 27.83 kPa and a high sensitivity of 0.73 kPa −1 in a low‐pressure regime (<1.6 kPa). Finally, pressure and strain sensing performance is demonstrated for the detection of human activities by mounting the sensor on various parts of the human body. The work reveals a new opportunity for the facile fabrication of high performance CCTO‐based capacitive sensors with multifunctional properties.