A joint research team led by Dr. Eun-Ho Sohn and Dr. Ju Hyeon Kim of the Korea Research Institute of Chemical Technology (KRICT, President Seokmin Shin) and Prof. Jin Woo Bae of the School of Energy, Materials and Chemical Engineering at the Korea University of Technology and Education (KOREATECH, President Kil-Sang Yoo) has developed self-powered fibers using a simple spray-coating process that blends two different polymers, eliminating the need for high-voltage equipment.
The technology is expected to simplify conventional complex fiber fabrication processes and facilitate the manufacturing of smart sensors and wearable electronic devices based on triboelectricity.
When two different materials come into contact and then separate, small electrical charges are generated, similar to static electricity. A triboelectric nanogenerator (TENG) converts this phenomenon into electrical energy. Improving the output of a TENG requires both an enlarged effective contact area between the two materials and effective suppression of charge leakage.
One approach is to fabricate the triboelectric material into very fine polymer fibers. Conventional methods, however, have generally required high-voltage equipment to produce the fibers, followed by additional coating processes to suppress charge dissipation. These complicated manufacturing steps also pose challenges for large-area fabrication.
The research team developed a one-step spray-coating process by blending poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE), a fluorinated polymer with strong electron-withdrawing characteristics, with polydimethylsiloxane (PDMS), a silicone-based polymer with excellent charge-trapping capability. The paper describes P(VDF-TrFE) as a tribo-negative material with high electronegativity and PDMS as a material capable of retaining charges through deep physical and chemical traps.
A higher proportion of the polar β-phase in P(VDF-TrFE) is favorable for enhancing triboelectric performance because it promotes dipole alignment and charge generation. Conventional electrospinning uses a strong electric field to align polymer chains and facilitate β-phase formation. In the newly developed process, however, the polymer solution experiences shear and extensional deformation as it passes through the spray nozzle and is atomized, partially stretching and orienting the P(VDF-TrFE) chains. Rapid solvent evaporation then kinetically freezes these deformed chain conformations before they can fully relax, thereby promoting β-phase crystallization without an applied high-voltage electric field.
The two polymers also spontaneously separate according to their different surface energies as the sprayed material dries. PDMS, which has the lower surface energy, preferentially migrates toward the outer surface, while P(VDF-TrFE) becomes enriched in the interior. Rapid solidification preserves this vertically graded composition, naturally forming a self-stratified structure without an additional coating step.
Rather than forming an ideal core-shell structure with a sharp interface, the process produces a compositionally graded architecture consisting of a PDMS-enriched exterior and a P(VDF-TrFE)-rich interior. The P(VDF-TrFE)-rich interior promotes β-phase-assisted charge generation, while the PDMS-enriched exterior enhances charge retention by suppressing charge dissipation.
Performance testing showed that the optimized TENG generated an open-circuit voltage (Voc) of 290 V, a short-circuit current (Isc) of 7.5 µA, and a maximum power density of 1.23 W/m². This level of performance demonstrates its potential for use in sensors for small electronic devices. The device also maintained stable output over 30,000 contact-separation cycles, demonstrating excellent durability.
The research team also fabricated a smart door-lock system incorporating a keypad consisting of 12 individual TENG sensors. Each key generated an electrical signal when pressed, allowing the system to recognize a password and operate the locking mechanism. This demonstration confirmed that the newly developed material can function not only as an energy harvester but also as a self-powered sensor for human-machine interfaces, without requiring an external power source for input detection.
In the demonstrated system, the 12 TENG units were arranged as a 3 × 4 keypad and connected to an Arduino Mega microcontroller, which distinguished between correct and incorrect password inputs and controlled the door-lock mechanism.
The study was published in September 2026 in Advanced Composites and Hybrid Materials, an international journal in the field of composite materials (Impact Factor: 15.5; top 4.3% in JCR). Insun Woo, a Ph.D. candidate at KOREATECH, and Chaelin Park, a master’s student at the University of Science and Technology (UST), served as co-first authors. Prof. Jin Woo Bae of KOREATECH, Principal Researcher Eun-Ho Sohn of KRICT and UST, and Principal Researcher Ju Hyeon Kim of KRICT served as co-corresponding authors.

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KRICT is a non-profit research institute funded by the Korean government. Since its foundation in 1976, KRICT has played a leading role in advancing national chemical technologies in the fields of chemistry, material science, environmental science, and chemical engineering. Now, KRICT is moving forward to become a globally leading research institute tackling the most challenging issues in the field of Chemistry and Engineering and will continue to fulfill its role in developing chemical technologies that benefit the entire world and contribute to maintaining a healthy planet. More detailed information on KRICT can be found at https://www.krict.re.kr/eng/
The research was supported by the Basic Science Research Program (Mid-Career Researcher Program) of the Ministry of Science and ICT and the National Research Foundation of Korea (RS-2024-00348475), the BK21 FOUR Program of the Ministry of Education, the KRICT Core Research Program, and the Materials/Components Technology Development Program funded by the Ministry of Trade, Industry and Resources and administered by the Korea Planning & Evaluation Institute of Industrial Technology (RS-2026-25542711).