Highly sensitive electronic whiskers based on patterned carbon nanotube and silver nanoparticle composite films

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 111; no. 5; pp. 1703 - 1707
• Main Authors: Takei, Kuniharu, Yu, Zhibin, Zheng, Maxwell, Ota, Hiroki, Takahashi, Toshitake, Javey, Ali
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 04.02.2014; National Acad Sciences
• Subjects: Animals; Bending; Carbon nanotubes; Composite materials; Electric potential; Electrical resistivity; Electricity; Electrodes; Electronics - instrumentation; Humans; Material films; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Nanocomposites - chemistry; Nanocomposites - ultrastructure; Nanoparticles; Nanotubes; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - ultrastructure; Physical Sciences; Sensors; Silver; Silver - chemistry; Thin films; Vibrissae; Wind; artificial devices; flexible electronics; nano materials; strain sensors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1317920111

Mammalian whiskers present an important class of tactile sensors that complement the functionalities of skin for detecting wind with high sensitivity and navigation around local obstacles. Here, we report electronic whiskers based on highly tunable composite films of carbon nanotubes and silver nanoparticles that are patterned on high-aspect-ratio elastic fibers. The nanotubes form a conductive network matrix with excellent bendability, and nanoparticle loading enhances the conductivity and endows the composite with high strain sensitivity. The resistivity of the composites is highly sensitive to strain with a pressure sensitivity of up to ∼8%/Pa for the whiskers, which is >10× higher than all previously reported capacitive or resistive pressure sensors. It is notable that the resistivity and sensitivity of the composite films can be readily modulated by a few orders of magnitude by changing the composition ratio of the components, thereby allowing for exploration of whisker sensors with excellent performance. Systems consisting of whisker arrays are fabricated, and as a proof of concept, real-time two- and three-dimensional gas-flow mapping is demonstrated. The ultrahigh sensitivity and ease of fabrication of the demonstrated whiskers may enable a wide range of applications in advanced robotics and human–machine interfacing.