In this work, the surface modification using a two-steps plasma etching has been developed for enhancing energy conversion performance in polytetrafluoroethylene (PTFE) triboelectric nanogenerator (TENG). Enhancing surface area by a powerful O₂ and Ar bipolar pulse plasma etching without the use of CF₄ gas has been demonstrated for the first time. TENG with modified surface PTFE using a sequential two-step O₂/Ar plasma has a superior power density of 9.9 Wm⁻², which is almost thirty times higher than that of a pristine PTFE TENG. The synergistic combination of high surface area and charge trapping sites due to chemical bond defects achieved from the use of a sequential O₂/Ar plasma gives rise to the intensified triboelectric charge density and the enhancement of power output of PTFE-based TENG. The effects of plasma species and plasma etching sequence on surface morphologies and surface chemical species were investigated by a field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The correlation of surface morphology, chemical structure, and TENG performance was elucidated. In addition, the applications of mechanical energy harvesting for lighting, charging capacitors, keyboard sensing and operating a portable calculator were demonstrated.

In this study, the silicon-based interlayers for hydrogenated amorphous carbon (a-C:H) coating on a chromium-plated substrate are presented. The a-Si, a-Si:N, a-Si:H and a-Si_xC_y:H interlayers with a thickness of about 306 nm were deposited by direct current magnetron sputtering technique. The a-C:H films with a thickness of about 317 nm was prepared as a top layer by radio frequency-plasma chemical vapor deposition. The a-C:H films with silicon-based interlayers were characterized by x-ray photoelectron spectroscopy, Raman spectroscopy, field emission-secondary electron microscopy, nanoindentation, micro-scratching, and electrochemical corrosion measurements in terms of their structure, morphology, mechanical and adhesive properties, and corrosion resistance. The a-C:H films with an a-Si:H interlayer exhibit the lowest corrosion current density, which is about 36 times lower than that of the uncoated chromium-plated substrate. In addition, the hardness increases from 8.48 GPa for the uncoated substrate to 20.98 GPa for the a-C:H/a-Si:H sample. The mixing with hydrogen gas could reduce the residual oxygen during the deposition process, which could reduce the Si–O bonding and improve the adhesion strength between the a-C:H film and the a-Si:H interlayer and the a-Si:H interlayer and the substrate. Therefore, it can be concluded that the protective a-C:H coating with an a-Si:H interlayer has excellent potential to significantly improve the durability and extend the service life of materials used in abrasive and corrosive environments.

Increasing energy demands and growing environmental concerns regarding the consumption of fossil fuels are important motivations for the development of clean and sustainable energy sources. A triboelectric nanogenerator (TENG) is a promising energy technology that harnesses mechanical energy from the ambient environment by converting it into electrical energy. In this work, the enhancement of the energy conversion performance of a natural rubber (NR)-based TENG has been proposed by using modified activated carbon (AC). The effect of surface modification techniques, including acid treatments and plasma treatment for AC material on TENG performance, are investigated. The TENG fabricated from the NR incorporated with the modified AC using N₂ plasma showed superior electrical output performance, which was attributed to the modification by N₂ plasma introducing changes in the surface chemistry of AC, leading to the improved dielectric property of the NR-AC composite, which contributes to the enhanced triboelectric charge density. The highest power density of 2.65 mW/m² was obtained from the NR-AC (N₂ plasma-treated) TENG. This research provides a key insight into the modification of AC for the development of TENG with high energy conversion performance that could be useful for other future applications such as PM2.5 removal or CO₂ capture.

This work aims to develop a multihole atmospheric pressure plasma jet (APPJ) device to increase the plasma area and apply it to a continuous seed treatment system. Broccoli seed was used to study the effects of an atmospheric pressure plasma jet on seed germination and growth rate. An argon flow rate of 4.2 lpm, a plasma power of 412 W, and discharge frequency of 76 kHz were used for seed treatment. The contact angle decreased strongly with the increase in treatment time from 20 s to 80 s. The broccoli seed’s outer surface morphology seemed to have been slightly modified to a smoother surface by the plasma treatment during the treatment time of 80 s. However, the cross-sectional images resulted from Synchrotron radiation X-ray tomographic microscopy (SRXTM) confirmed no significant difference between seeds untreated and treated by plasma for 80 s. This result indicates that plasma does not affect the bulk characteristics of the seed but does provide delicate changes to the top thin layer on the seed surface. After seven days of cultivation, the seed treated by plasma for 30 s achieved the highest germination and yield.