A flexible three-electrode dielectric barrier discharge source with high stability and activity for plasma sterilization

Abstract Flexible plasma sources have emerged as a transformative technology for fresh food sterilization due to their unique conformability to complex surfaces and broad size adaptability. However, challenges still remain in achieving consistent discharge stability and controlled characteristics. In this work, an innovative flexible surface dielectric barrier discharge (SDBD) sheet with a three-electrode configuration (3E-SDBD) was successfully designed to enhance the discharge performance. The discharge characteristics in terms of discharge intensity, power consumption, electric field strength, emission and electron density as well as thermal stability were evaluated under various applied voltages. A traditional two-electrode SDBD source (2E-SDBD) was used as a benchmark for comparative analysis. The sterilization performance of these two SDBD sources were also compared using the typical bacterial species Escherichia coli . Compared with the conventional 2E-SDBD, the 3E configuration in the 3E-SDBD source significantly lowered the breakdown voltage in air and generated a more uniform discharge distribution over the electrode surface. Moreover, the novel 3E-SDBD source exhibited superior discharge power, reduced electric field strength and electron density ascribed to the synergy between the vertical and horizontal electric fields, while maintaining higher thermal stability under the same applied voltage with the 2E-SDBD source, which contributed to the higher sterilization performance in the 3E-SDBD source. A sterilization rate of nearly 100% was achieved within just 30 s using the 3E-SDBD source, whereas the conventional 2E-SDBD required approximately 120 s to reach the same level of effectiveness. These findings indicate that the proposed 3E-SDBD source is reliable to be used in packed food processing applications in the future.