Professor Yang Yang’s team at San Diego State University and Professor Ziyu Wang’s team at Wuhan University—New progress in piezoelectric composite materials research

• Research Background

  Due to the need for integrated sensing and protection, lightweight, durable, and smart bioelectronic sensors have been extensively researched and developed in the fields of sports and gerontology. However, smart sensing capabilities and high-intensity protection do not go hand in hand. For example, although state-of-the-art biomonitoring wearable electronics rely on soft piezoelectric materials or flexible printed circuit boards (F-PCBs), they often lack adequate protection capabilities. Advanced armor, on the other hand, is made from a combination of strong organic fibers, metals or inorganic ceramics, but this doesn't work well with sensors. Future applications will require combining sensing and protection functions to create multifunctional wearable sensors, which will require new manufacturing strategies to achieve.

  
  

  
  

  The basis of the structural design of multifunctional sensors is to learn from and construct organisms with specific microstructures in nature. For example, after thousands of years of evolution, cuttlefish have developed a hard cuttlefish bone structure that can remain stable in the high-pressure environment of the deep sea and exhibit excellent protective properties. Key to this performance is its unique cavity wall spacer microstructure, which provides both high stiffness and energy absorption, making it an excellent model for multifunctional sensor design.

• Based on the above, the team of Professor Yang Yang from San Diego State University and the team of Professor Ziyu Wang from Wuhan University collaborated to propose a new strategy. They grew recyclable, repairable piezoelectric Rochelle Salt Crystals into 3D printed cuttlebone-inspired structures to form new reinforced composites for smart detection. The research results were published in the journal Nature Communications under the title "Growing Recyclable and Healable Piezoelectric Composites in 3D Printed Bioinspired Structure for Protective Wearable Sensor".

  
  

  Highlights of graphics and text

  
  

  1. RS crystals were grown in 3D printed cuttlebone structures, and these crystals were used to create smart monitoring devices with integrated mechanical protection and sensing functions.

  
  

  2. The synthesis and piezoelectric performance mechanism of RS crystals in the 3D printed cuttlefish bone structure, namely 3D printed Rochelle salt cuttlefish bone composite (RSC), were studied.

  
  

  3. The composite material produced exhibits excellent piezoelectric and mechanical properties, as well as excellent repairability and recyclability.

  
  

  4. Smart array armor and kneepads based on 3D printed RSC can detect the location and size of the force exerted on the wearer. These research results lay the foundation for a new generation of intelligent monitoring and detection electronic devices for various applications such as sports, medicine, military and aerospace.

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• Figure 1. Design and crystal growth process of 3D printed RSC a) Schematic diagram of bionic 3D printed cuttlefish bone structure and RS crystal growth process; b) Pictures of crystal growth at different times in the 3D printed structure; CT scan of the sample and EDX elements of the sample Analysis; c) Photos of multiple 3D printed complex structures of artificial cuttlebone, demonstrating the design flexibility of this 3D printing method.
  

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• Figure 2. Study and comparison of mechanical properties of 3D printed RSCs
  

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• Figure 3. Study on the recycling and repair performance of 3D printed RSC a) Schematic diagram and photos of the process of repairing damaged 3D printed RSC samples by dripping RS solution through a syringe; b) Photos of the 3D printing-RSC recycling process; c) Original 3D printed RSC samples Comparison with the piezoelectric response of recycled and repaired samples; d) Comparison of mechanical properties of original samples, repaired samples, and recycled samples; e) Fracture toughness (KIC) and flexural strength (KF) of original, healed, and recycled 3D printed RSC samples ) Compare.
  

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• Figure 4. Application of composite materials in intelligent fall detection protection enhanced knee pads a) Knee pad schematic diagram and pictures, and knee pad alarm detection test; b) MATLAB component block distribution and voltage waveform of the output voltage obtained from the intelligent knee pad fall test; c) Intelligent The voltage output waveform and MATLAB piezoelectric element block distribution data collection of knee pads sensing different degrees of falls (including mild falls, moderate falls, and severe falls).

• Growing Recyclable and Healable Piezoelectric Composites in 3D Printed Bioinspired Structure for Protective Wearable Sensor

  
  

  https://www.nature.com/articles/s41467-023- 41740-6