The world is quickly moving towards an era of advanced technology and automation. This includes the development of more advanced sensors and robots. However, the current options are expensive and not very sensitive. In a recent study, researchers from Japan addressed these issues by creating a new type of piezoelectric composite material using electrospun polyvinylidene fluoride nanofibers combined with dopamine. Sensors made from this material showed significant improvements in performance and stability at a low cost. This promises to advance the fields of medicine, healthcare, and robotics.The advancements in technology, including artificial intelligence and robotics, are transforming the way we live and work. Often overlooked, sensors play a crucial role in bridging the gap between humans, machines, and the environment.
With the rise of agile robots and wearable electronics, traditional silicon-based sensors are no longer sufficient for many applications. As a result, there is a growing focus on developing flexible sensors that offer improved comfort and versatility. Piezoelectric sensors are especially significant in this area, as they are capable of converting mechanical stress and movements into electrical signals.Converting mechanical energy into an electrical signal is a challenging task. Despite many promising methods, there is still a need for sustainable ways to mass-produce flexible, high-performance piezoelectric sensors at a low cost.
To address this issue, a team of researchers from Shinshu University in Japan decided to enhance the design of flexible piezoelectric sensors using electrospinning, a well-established manufacturing technique. Their latest study, led by Distinguished Professor Ick Soo Kim and his team, was published on 2 May 2024, in the journal.The new sensor design proposed in Nature Communications involves creating a composite 2D nanofiber membrane through a stepwise electrospinning process. Initially, nanofibers of polyvinylidene fluoride (PVDF) with diameters around 200 nm are spun to form a strong and uniform network, which serves as the basis for the piezoelectric sensor. Subsequently, even finer PVDF nanofibers with diameters smaller than 35 nm are spun onto the existing network, automatically interweaving between the gaps to create a unique 2D structure. This design was thoroughly characterized through experiments, simulations, and theoretical analyses by the researchers.Researchers discovered that the composite PVDF network had an improved beta crystal orientation, which enhanced the polar phase responsible for the piezoelectric effect in PVDF materials. This enhancement significantly improved the piezoelectric performance of the sensors. To further increase the stability of the material, the researchers added dopamine (DA) during the electrospinning process, creating a protective core-shell structure.
“Sensors made from PVDF/DA composite membranes showed excellent performance, with a wide response range of 1.5-40 N and high sensitivity of 7.29 V/N to weak forces in the range. An outstanding feature of these sensors is their high sensitivity, reliable performance, and long-lasting durability,” Kim comments. These exceptional characteristics were demonstrated in practical experiments using wearable sensors to measure a wide range of human movements and activities. Specifically, the sensors proposed could generate a distinct voltage response to natural movements and physiological signals when worn by a human. These included activities such as finger tapping, knee and elbow bending, foot stamping, speaking, and wrist pulses.
Considering the potential for low-cost mass production of these piezoelectric sensors, along with their use of environmentally friendly organic materials instead of harmful inorganic substances, they hold promise.nics, this research could have significant technological implications not just for health monitoring and diagnostics, but also for robotics. Kim ponders, “Despite the current challenges, humanoid robots are set to play a more and more important role in the very near future. For example, the well-known Tesla robot ‘Optimus’ is already capable of imitating human movements and walking like a human.” Kim continues, “Considering that advanced sensors are currently being used to monitor robot movements, our proposed nanofiber-based superior piezoelectric sensors have the potential not only for monitoring human movements, but also in the field of humanoid robotics.”
In order to facilitate the adoption oTo make these sensors more user-friendly, the team is prioritizing enhancements to the material’s electrical output properties. This will allow for flexible electronic components to operate without relying on an external power source. Advancements in this area have the potential to expedite our journey towards the era of intelligent technology, ultimately leading to more convenient and sustainable lifestyles.
