Professor Chang-Gyu Jeong (College of Engineering, Division of Advanced Materials Engineering) has succeeded in identifying the mechanism by which the composition of piezoelectric polymer materials—materials that generate electricity when pressed—improves the performance of nanofibers.

The results were published in the April issue of Small (IF = 13.281), a leading international journal in the field of nanoscience, and were selected as a cover article.

‘Piezoelectric’ refers to the property whereby a mechanical force applied externally produces a voltage, or conversely, an applied voltage produces a deformation. Most piezoelectric materials are rigid ceramics. However, materials composed of different polymers in the polyvinylidene fluoride (PVDF) family have been widely studied because they offer advantages such as mechanical flexibility and high electrical insulation. Compared with ceramics, research on the principles and mechanisms underlying these polymer-based composite materials remains relatively limited.

Recent reports indicated that within PVDF-based copolymers, the piezoelectric properties can increase sharply depending on the composition of two different monomers. However, it was not known whether this effect also holds under widely used processing methods that are suitable for developing polymer fiber devices.

To investigate this, Professor Jeong’s team fabricated thin nanofiber structures from PVDF-based polymer composite materials using the electrospinning process, a simple method capable of producing large-area fibrous structures. This electrospinning method has recently been widely applied in the production of mask filters and similar products.

The team established sample fabrication and measurement conditions for electrospinning and produced PVDF nanofibers with various compositions. In piezoelectric ceramics, there are composition ranges where piezoelectric properties increase; they confirmed that similar behavior can occur in polymer fibers. Ultimately, they demonstrated that this can improve the performance of piezoelectric sensors and energy devices. These findings are expected to be widely applicable to the development of next-generation wearable devices.

As a result of these achievements, Professor Jeong has been invited as a speaker to the Materials Research Society (MRS), an organization recognized as one of the most prestigious societies in the materials field. At the upcoming MRS conference, he will deliver an invited lecture and serve as chair for several symposium sessions.

Professor Chang-Gyu Jeong said, 'This research can further stimulate interest in fundamental studies of piezoelectric polymers and be applied to the development of wearable devices. Following 2020, I am honored to be selected again as an invited speaker at MRS this year.'

Meanwhile, this research was conducted with support from the Mid-Career Researcher Program in Science and Engineering funded by the Ministry of Science and ICT and the National Research Foundation of Korea.