Nanoscale architectures found in nature have unique functionalities and their discovery has led to significant advancements in various fields including optics, wetting, and adhesion. The sensilla of arthropods, comprised of unique hierarchical structures, are a representative example which inspired the development of various bioinspired systems, owing to their hypersensitive and ultrafast responsivity to mechanical and chemical stimuli. This report presents a geometry-switchable and highly H2-reactive Janus nanofiber (H-NF) array inspired by the structural features of the arthropod sensilla. The H-NF array (400 nm diameter, 4 µm height, 1.2 µm spacing distance, and hexagonal array) exhibits reversible structural deformation when exposed to a flammable concentration of hydrogen gas (4 vol% H2 in N2) with fast response times (5.1 s). The structural change can be detected with the bare eye, which is a result of change in the optical transmittance due to the structural deformation of the H-NF array. Based on these results, an eye-readable H2-sensor that requires no additional electrical apparatus is demonstrated, including wetting-controllable H2-selective smart surfaces and H2-responsive fasteners.
Bibliographical noteFunding Information:
This work was supported by the Priority Research Centers Program (2012-0006689) through the National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science and Technology (MEST) and Mid-Career Researcher Program through NRF grant funded by the MEST (2014R1A2A2A09053061), and the R&D program of MOTIE/KEIT [10064081, Development of fiber-based flexible multimodal pressure sensor and algorithm for gesture/posture-recognizable wearable devices]. We gratefully acknowledge partial support from the National Research Foundation of Korea (NRF-2017K2A9A2A06013377, NRF-2017M3A7B4049466, NRF-2014R1A1A1007162, and NRF-2016H1A2A1908670). This material is also based upon work supported by the Ministry of Trade, Industry & Energy (MOTIE, Korea) under Industrial Technology Innovation Program. No. 10062694, ?Development of nano-materials hybrid fibers and bio-signal sensors for safety underwears of heavy workers?. This work also supported by the Natural Science Foundation of China (Nos. 51322201 and U1632115). In addition, the authors thank Tanaka Kikinzoku Kogyo K.K. for comments on the usage and properties of palladium. The Acknowledgements and Figure were updated on August 4, 2017, following initial online publication.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics