The 20th International Symposium on Electrets (ISE 20) was held in Matsue, Japan, at the “Kunibiki Messe” Shimane Prefectural Convention Center from September 1 to 5, 2025 (Figs. 1 and 2). This event was sponsored by the IEEE Dielectrics and Electrical Insulation Society, and hosted by Prof. Yuji Suzuki of The University of Tokyo and Prof. Takashi Nakajima of Tokyo University of Science.

More than 100 participants from 15 countries across Asia, Europe, and North America attended to discuss and exchange the latest advances in electret science, dielectric materials, and electrostatic phenomena. By bringing together experts from academia and industry, ISE 20 provided an international platform for the exchange of research findings and innovative ideas, contributing to future advances in both scientific understanding and practical technologies. The symposium also strengthened international collaborations and promoted interdisciplinary research, reinforcing the important role of electret science in emerging technologies such as energy harvesting, flexible electronics, sensors, and biomedical applications.

The scientific sessions include the Bernhard Gross Memorial Lecture delivered by Prof. Michael Wu bbenhorst (KU Leuven), 6 plenary lectures, 47 oral presentations, and 41 poster presentations. A special tribute session was also held to honor Eiichi Fukada. Attendees also enjoyed exploring Matsue city, a historic castle town known for its beautiful lakes, traditional tea culture, and rich heritage.

Preceding ISE 20, a tutorial session with four lectures on recent topics in electrets was given by Prof. Xiaoqing Zhang (Tongji University), Prof. Masahiro Sato (The University of Tokyo), Prof. Yuji Suzuki (The University of Tokyo), and Prof. Yumi Tanaka (Tokyo University of Science). This was followed by a Special Session on the “100th Anniversary of Mototaro Eguchi’s Carnauba-Wax Electret.” In this session, to celebrate 100 years from his first article on electret in, “a short history of Mototaro Eguchi” by Prof. Yuji Suzuki (The University of Tokyo), “surface potential measurements of the Eguchi’s Electret in 2024” by Dr. Yoshinobu Yasuno (Kobayashi Institute of Physical Research), “Mototaro Eguchi and physics in early 20th-century Japan” by Dr. Hiroto Kono (National Museum of Nature and Science, Japan), and “early electret research after Eguchi’s seminal work by Prof. Reimund Gerhard (University of Potsdam) were given.

During the closing ceremony of ISE 20, the 2025 Dilip Das-Gupta Award for Best Presentation by Young Scientist was awarded to “extension of piezoelectret theory and its importance for the development of piezoelectret metamaterials,” by Qianqian Hu at Togji University, “self-powered piezo-/pyroelectric integrated devices using electrospun fluoropolymer electret fibers,” by Krittish Roy at University of Limerick, and “gait detection system using piezoelectric matrix sensor” by Yuki Sakurai at Tokyo University of Science.

In ISE 20, research presentations covered a wide range of topics, including charge injection/transport/trapping; decay mechanisms in dielectric materials; ferroelectric, piezoelectric, and pyroelectric materials; organic and polymer electronics and transducers; bioelectrets and biomaterials; nanoscale electrostatic phenomena; and advanced characterization techniques. Considerable attention was also given to emerging applications such as flexible and stretchable electronics, wearable sensors, actuators, electret/triboelectric energy harvesting devices, microelectromechanical systems (MEMSs), and sustainable energy technologies.

This Special Issue of the IEEE Transactions on Dielectrics and Electrical Insulation covers these topics with a collection of 20 carefully reviewed papers, most of which were presented at ISE 20. These contributions provide a state-of-the-art overview of electret science and applications, demonstrating its interdisciplinary reach across condensed matter physics, chemistry, materials science, electrical/mechanical engineering, and life sciences.

We extend our sincere appreciation to all the authors and reviewers for their valuable contributions and support. We also thank the Editor-in-Chief, Prof. Michael Wübbenhorst, for his pivotal role in making this Special Issue possible. Finally, we thank all the participants, the Scientific Advisory Committee of ISE, benefactors, and sponsors, whose contributions greatly enhanced the organization and scientific quality of the symposium.

Post-operative infections remain a challenge in implant surgery, leading to prolonged treatment, increased costs, and implant failure. Localized antibiotic-delivery coatings are a promising strategy to reduce infection risk while maintaining biocompatibility. Here, we evaluate cold atmospheric pressure plasma (CAP) spraying as a solvent-free method to deposit polyvinyl alcohol (PVA) layers containing amikacin on stainless steel and to identify plasma parameters that control release and antibacterial activity. A 3 × 3 factorial design varied nozzle distance (15, 20, 25 mm) and speed (10, 15, 20 cm/s). Surface morphology was assessed by optical microscopy, amikacin release quantified by HPLC-HRMS, and antibacterial activity tested against Staphylococcus aureus and Escherichia coli using Kirby–Bauer disc diffusion. Two-way ANOVA with Tukey post hoc tests and nonparametric validation were applied. Cold plasma spraying speed significantly affected drug release, whereas distance and the interaction term were not significant. Lower spraying speeds produced thicker, more porous coatings with greater cumulative release and larger inhibition zones. Drug release profiles were best described by Weibull and first-order models, showing an initial burst followed by sustained release. These findings indicate that CAP spraying enables solvent-free fabrication of antibiotic-loaded PVA coatings with tunable release, and optimizing spraying speed improves coating mass, drug delivery, and antibacterial performance.