Inspired by bats’ wing membranes, a newly developed flexible and self-adaptive airflow sensor displays potential for wearable electronics and contact-free manipulation.
As the only mammal that can fly, bats differ from birds in that they have much more flexible wings, allowing them to change its conformation with extraordinary dexterity and precision. The skin of bat’s wing membranes, unlike human skin, are saturated with a whole series of muscles. These muscles that contract and relax in every wingbeat cycle, changes the stiffness of the membrane, giving bats incredible control over their wings.
Inspired by the unique airflow sensing capabilities of bats’ wing membranes, researchers at the Ningbo Institute of Materials Technology and Engineering of the Chinese Academy of Sciences looked at how they can improve upon airflow sensors and successfully developed a flexible and self-adaptive airflow sensor that is mediated by the reversible microspring effect.
Airflow sensors based on mechanical deformation mechanisms have been receiving much attention due to their exceptional flexibility and sensitivity. However, constructing a highly sensitive and self-adaptive airflow sensor through a simple, controllable, and scalable method has proven to be difficult.
The research team led by Professor Chen Tao constructed graphene/single-walled nanotubes (SWNTs)-Ecoflex membrane (GSEM), which can be swiftly transferred and adapted to distinct flat/bend and smooth/rough surfaces.
When airflow was applied, the microscale deformation of interlayer SWNTs led to significant changes in contact resistance, enhancing the developed GSEM-based airflow sensor with better properties like an ultralow airflow velocity detection limit, fast response time, and recovery time. As a result of the microspring effect, they have successfully built a highly sensitive and self-adaptive GSEM-based airflow sensor.
With this proof of concept, the GSEM-based airflow sensor can be engaged to achieve contact-free manipulation. By controlling the threshold, it can be implemented in a smart window system to attain intelligent open and close behaviours.
Furthermore, the team devised multiple airflow sensors to discriminate the magnitude and spatial distribution of the applied airflow stimulus. Being combined into a wireless vehicle model system, the GSEM-based airflow sensor can precisely capture information of flow velocity to obtain real-time manipulation of motion direction.
This microspring effect-based airflow sensing system displays great potential in the fields of wearable electronics and contact-free smart manipulation.
Source: Zhou et al. (2021). Bionic Adaptive Thin-Membranes Sensory System Based on Microspring Effect for High-Sensitive Airflow Perception and Noncontact Manipulation. Advanced Functional Materials, 2105323.