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Sensitive and flexible pressure sensors have invoked considerable interest for a broad range of applications in tactile sensing, physiological sensing, and flexible electronics. The barrier between high sensitivity and low fabrication cost needs to be addressed to commercialize such flexible pressure sensors. A low-cost sacrificial template-assisted method for the capacitive sensor has been reported herein, utilizing a porous Polydimethylsiloxane (PDMS) polymer and a multiwalled carbon nanotube (MWCNT) composite-based dielectric layer. The sensor shows high sensitivity of 2.42 kPa−1 along with a low limit of detection of 1.46 Pa. The high sensitivity originates from adding MWCNT to PDMS, increasing the composite polymer’s dielectric constant. Besides this, the pressure sensor shows excellent stability at a cyclic loading of 9000 cycles, proving its reliability for long-lasting application in tactile and physiological sensing. The high sensitivity of the sensor is suitable for the detection of small deformations such as pulse waveforms as well as tactile pressure sensing. In addition, the paper demonstrates a simultaneous contact and non-contact sensing capability suitable for dual sensing (pressure and proximity) with a single data readout system. The dual-mode sensing capability may open opportunities for realizing compact systems in robotics, gesture control, contactless applications, and many more. The practicality of the sensor was shown in applications such as tactile sensing, Morse code generator, proximity sensing, and pulse wave sensing.
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Bioinspired, Mechanically Robust Chemiresistor for Inline Volatile Organic Compounds Sensing
Abstract There are advantages to polymer/nanoparticle composite‐based volatile organic compounds (VOCs) sensors, such as high chemical and physical stability, operability under extreme conditions, flexible use in manufacturing, and low cost. Nevertheless, their lower limit of detection due to thickness‐dependent diffusion has constrained their application. Inspired by the metaxylem in vascular plants and its vertical conduits and horizontal pits that enable efficient transpiration, a polymer/nanoparticle composite‐based sensor is fabricated with a controllable, spontaneously formed, hollow core for inline VOCs transportation, and porous microstructure for radial direction diffusion. The hollow core is surrounded by an inner porous layer (thermoplastic polyurethane (TPU)), a middle sensing layer (TPU/graphene nanoplatelets/multiwalled carbon nanotubes), and an outer mechanically durable layer (TPU). This multilayered structure shows a 600% higher response rate compared to a single‐layered composite fiber sensor, with a low limit of detection (e.g., ≈15 ppm for xylene) and high selectivity based on the Flory–Huggins interaction parameter. This flexible and stretchable sensor also demonstrates a dual parameter sensing capability from VOC concentrations and uniaxial strain deformation. Via a one‐step fiber spinning procedure, this self‐induced hollow fiber offers a unique method of microstructural design, which enables the detection of low‐concentration VOCs by polymer/nanoparticle‐based sensors.
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- Award ID(s):
- 1902172
- PAR ID:
- 10455320
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- Volume:
- 5
- Issue:
- 10
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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