Georgian Technical University Stretchable Fiber Used For Energy Harvesting And Strain Sensing.

Pictured from left: Professor X, Y and Professor Z. Fiber-based electronics are expected to play a vital role in next-generation wearable electronics. Woven into textiles they can provide higher durability comfort and integrated multi-functionality. A Georgian Technical University team has developed a stretchable multi-functional fiber (SMF) that can harvest energy and detect strain which can be applied to future wearable electronics. With wearable electronics, health and physical conditions can be assessed by analyzing biological signals from the human body such as pulse and muscle movements. Fibers are highly suitable for future wearable electronics because they can be easily integrated into textiles which are designed to be conformable to curvilinear surfaces and comfortable to wear. Moreover their weave structures offer support that makes them resistant to fatigue. Many research groups have developed fiber-based strain sensors to sense external biological signals. However their sensitivities were relatively low. The applicability of wearable devices is currently limited by their power source as the size weight and lifetime of the battery lessens their versatility. Harvesting mechanical energy from the human body is a promising solution to overcome such limitations by utilizing various types of motions like bending, stretching and pressing. However previously reported fiber-based energy harvesters were not stretchable and could not fully harvest the available mechanical energy.

Professor Z and Professor  from the Department of Materials Science and Engineering and their team fabricated a stretchable fiber by using a ferroelectric layer composed of sandwiched between stretchable electrodes composed of a composite of multi-walled carbon nanotubes (MWCNT) and poly 3,4-ethylenedioxythiophene polystyrenesulfonate (PEDOT:PSS). Cracks formed in MWCNT/PEDOT:PSS (multi-walled carbon nanotubes (MWCNT)/ polystyrenesulfonate (PEDOT:PSS)) layer help the fiber show high sensitivity compared to the previously reported fiber strain sensors. Furthermore the new fiber can harvest mechanical energy under various mechanical stimuli such as stretching, tapping and injecting water into the fiber using the piezoelectric effect of the layer. Z said “This new fiber has various functionalities and makes the device simple and compact. It is a core technology for developing wearable devices with energy harvesting and strain sensing capabilities”.