Flexible and wearable bionics-sensors, as the most exciting frontier in the field of flexible electronics, have attracted more and more attention due to their unique properties (attachable, wearable, and foldable) and potential applications in consumer electronics, homeland security, and health-related equipment etc. Microstructured polydimethylsiloxane (PDMS) film is considered to be the most popular flexible substrate to integrate sensitive nanomaterials for the flexible sensors due to its excellent elasticity and biocompatibility. However, the current fabrication method for patterned PDMS is complicated and expensive, requiring multi-steps (spin coating, lithography, and etching etc.). The large area integration based on self-assembled nanomaterial is also less reproducible.
Recently, researchers from the Suzhou Institute of Nanotech and Nanobionics (SINANO), Chinese Academy of Sciences (CAS), developed a simple and low-cost method for the fabrication of large-area uniformly microstructured PDMS thin films on which sensing nanomaterials are deposited. It is based on molding thin flexible PDMS on high-quality textiles such as silk. The microstructures on the silk surface are replicated onto PDMS. Combining silk-molded micro-patterned PDMS and a ultrathin layer deposition of single-walled carbon nanotubes, (reported previously in Journal of Materials Chemistry, 2012, 22, 21824-21827) it forms a new type of flexible artificial bionics-sensors with superior sensitivity (1.8 kPa-1), the lowest detectable pressure limit (0.6 Pa), fast response time (10 ms), and the highest stability (>67500 cycles) for detection of ultralow pressures. It can detect the weight of an ant or a bee. When attached to wrist, it can tell the difference in the heart beats between a pregnant person and a normal person. The result has been published in the latest issue of Advanced Materials, 2014, 26, 1336-1342, and was highlighted on its front cover.
"The PDMS pad has potential to use as a wearable sensor for blood pressure and heart beat monitoring. We are exploiting commercial applications of this ultra-sensitive flexible sensor in bionics and health care areas", says Prof. Ting Zhang, the lead researcher of this work.
Source: Chinese Academy of Sciences
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