Open AccessCarbon Nanofiber versus Graphene‐Based Stretchable Capacitive Touch Sensors for Artificial Electronic Skin
Author(s) -
Cataldi Pietro,
Dussoni Simeone,
Ceseracciu Luca,
Maggiali Marco,
Natale Lorenzo,
Metta Giorgio,
Athanassiou Athanassia,
Bayer Ilker S.
Publication year - 2018
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201700587
Subject(s) - materials science , graphene , capacitive sensing , silicone rubber , stretchable electronics , soft robotics , elastomer , electrode , electronic skin , composite material , nanotechnology , tactile sensor , elongation , fabrication , electronics , computer science , ultimate tensile strength , electrical engineering , actuator , medicine , chemistry , alternative medicine , engineering , pathology , artificial intelligence , robot , operating system
Stretchable capacitive devices are instrumental for new‐generation multifunctional haptic technologies particularly suited for soft robotics and electronic skin applications. A majority of elongating soft electronics still rely on silicone for building devices or sensors by multiple‐step replication. In this study, fabrication of a reliable elongating parallel‐plate capacitive touch sensor, using nitrile rubber gloves as templates, is demonstrated. Spray coating both sides of a rubber piece cut out of a glove with a conductive polymer suspension carrying dispersed carbon nanofibers (CnFs) or graphene nanoplatelets (GnPs) is sufficient for making electrodes with low sheet resistance values (≈10 Ω sq −1 ). The electrodes based on CnFs maintain their conductivity up to 100% elongation whereas the GnPs‐based ones form cracks before 60% elongation. However, both electrodes are reliable under elongation levels associated with human joints motility (≈20%). Strikingly, structural damages due to repeated elongation/recovery cycles could be healed through annealing. Haptic sensing characteristics of a stretchable capacitive device by wrapping it around the fingertip of a robotic hand (ICub) are demonstrated. Tactile forces as low as 0.03 N and as high as 5 N can be easily sensed by the device under elongation or over curvilinear surfaces.