Illustration of the use of organic semiconductor nanotubes to create artificial muscle. Mohammad Reza Abidian contributed the artwork. Credit: Mohammad Reza Abidian
Researchers at the University of Houston have reported a breakthrough in materials science and engineering through the creation of an electrochemical actuator using specialized organic semiconductor nanotubes.
The actuator is currently in its early stages of development. It will be a central part of future research in robotics, bioelectronics and biomedical sciences.
Mohammad Reza Abidian is an associate professor of biomedical and engineering at the UH Cullen College of Engineering. "Electrochemicals that convert electrical energy into mechanical energy have potential uses in many applications," he said. He is the corresponding author on the article "Organic Semiconductor Nanotubes For Electrochemical Devices", published in the journal Advanced Functional Materials. This article details the discovery.
For electrochemical actuators that work in liquid, significant movement (which scientists call actuation and measure it as deformation strain) has been difficult to achieve. The drag force of liquid limits actuator motion and limits ion transport and accumulation in electrode materials. Abidian and his team developed methods to work around these two obstacles in Abidian's laboratory.
"Our organic semiconductor nanotube electronic device has a high actuation performance, fast ion transport, accumulation and tunable dynamics when working with liquid and gel-polymer electrolytes. Abidian stated that this device has excellent performance. It also shows a low power consumption, high response, and excellent actuation stability.
He explained that the large effective surface area of the nanotubular structures is responsible for this outstanding performance. This allows for ion accumulation and transport, which leads to high electroactivity and endurance.
Abidian stated that the OSNT actuator's low power consumption and strain values, even when operating in liquid electrolyte is a significant improvement on previous electrochemical actuators. We evaluated the long-term stability. The organic semiconductor nanotube actuator demonstrated superior long-term stability to those previously reported with conjugated polymer-based actuators that operate in liquid electrolyte.
Mohammad Reza Abidian is an associate professor of biomedical and industrial engineering at the University of Houston Cullen College of Engineering. He announced a breakthrough in the development of an electrical actuator. Credit: University of Houston
Mohammadjavad Eslamian and Fereshtehsadat Mirathan, Vijay Krishna Raghunathan, Sheereen Majd were all part of the Department of Biomedical Engineering, UH Cullen College of Engineering.
Three scientists, Alan MacDiarmid, Hideki Shirakawa, and Alan J. Heeger discovered organic semiconductors called conjugated Polymers in the 1970s. They were awarded the Nobel Prize in 2000 for their discovery and development.
To be able to surpass the status quo with a new actuator, it must not only prove to be highly efficient (in this instance, in both liquid polymer electrolyte) but also last.
"To demonstrate the potential applications, we developed a micron-scale, movable neural probe based on OSNT microactuators. Abidian stated that this microprobe could be placed in the brain. This will allow neural signal recordings to be improved if they are affected by damaged tissue or neuron displacement.
Next is animal testing. This will take place at Columbia University. Initial results are expected by 2021. Longer term tests will follow.
Abidian stated that "considering the accomplishments so far, it is likely these new OSNT-based electronic devices will help advance our next generation of soft robots, artificial muscles and bioelectronics devices"
Learn more about the Water-driven soft actuator
Mohammadjavad Eslamian and colleagues, Organic Semiconductor Nanotubes For Electrochemical Devices, Advanced Functional Materials (2021). Information from the Journal: Advanced Functional Materials Mohammadjavad Eslamian and colleagues, Organic Semiconductor Nanotubes For Electrochemical Devices (2021). DOI: 10.1002/adfm.202105358
