International Journal of Engineering Research and Application www.ijera.com ISSN : 2248-9622 Vol. 9,Issue 1 (Series -II) Jan 2019, pp 71-76 www.ijera.com DOI: 10.9790/9622- 0901027176 71 | Page Studying the effect of the discharge modes of DBD plasma on the treatment of wool textiles Doaa. M. El-Zeer 1,2 1 Taif University, Alkhorma University College, Phys. Dep., KSA. 2 Center of plasma technology, Al-Azhar University, Nasr City, Cairo, Egypt. *Corresponding Author: Doaa. M. El-Zeer ABSTRACT In the present study a comparison between the influence of the atmospheric pressure glow discharge APGD mode and the filamentary discharge FD mode on the treatment of the wool textiles has been reported at different conditions of the current and treatment time. The induced changes in wool properties, such as the wettability, surface morphology and printability properties have been investigated. The surface characterization was performed using SEM and FTIR imaging. It has been discovered that APGD mode of DBD plasma is more efficient than FD mode. It has been found that the concentration of nitrogen excited species that are the responsible for the surface activation of the wool textile in APGD is more than its concentration in FD mode. KEYWORDS: DBD modes, Atmospheric pressure glow discharge APGD mode, Filamentary discharge FD mode, wool treatment -------------------------------------------------------------------------------------------------------------------------------------- Date Of Submission: 16-01-2019 Date Of Acceptance:28-01-2019 -------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION Recently, the dielectric barrier discharge DBD plasma can be used as an effective technique for modifying the surface properties of wool fabric such as its whiteness, wettability, shrinkage, printability, surface morphology, mechanical properties, dyeability, and fastness properties without much alternation to the interior of the fiber. In this work, two different modes of DBD have been examined to discover the best conditions for modifying the wool fiber properties. These modes are the filamentary mode FD and the atmospheric pressure glow discharge APGD mode. In filamentary FD plasma the electrical breakdown starts simultaneously at many points of the surface as a short-lived microdischarges of about 100 μm radius, each one generated from a streamer breakdown. Due to the short duration of the microdischarges and their small volume in comparison with the entire gas gap, plasma remains strongly non-thermal. When a filamentary discharge occurs multiple current pulses per half cycle are observed [1]. In the glow APGD plasma a uniform region extending uniformly over the whole electrode surface. Some conditions should be verified to obtain the glow mode at atmospheric pressure: a high number of seed electrons, an ionization mechanism under low fields, a high value of the dielectric secondary emission coefficient. In order to avoid streamers formation electrons should be produced in small electric field. As an intense space-charge is not generated, ions have time to reach the cathode to promote the secondary electrons emission, so an increase of ion density is also necessary. Besides the electron-neutral collisions, metastables species play an important role in promoting ionization by Penning effect. An increase of the ionization and of the number of electrons emitted from the cathode is not only sufficient to ensure a glow regime but also the number of electrons remaining in the gas before the occurrence of a new discharge is quite important. As the electrons arrive at the insulator surface under low electric fields, they are slightly trapped: this is called memory effect. These electrons can be easier released in the next half period enhancing the value of secondary cathode emission and thus enhancing the probability of obtaining a glow discharge [1] and [2]. II. EXPERIMENTAL DETAILS 2.1. Plasma Set up Figure (1) represents two discharge cells of APGD and of FD plasmas. These two cells have the same dimensions except for the type of the dielectric barrier. In the APGD cell the dielectric barrier is a commercial porous fiber while in the FDBD cell the barrier is a Pyrex glass. It has been found that changing the type of the dielectric RESEARCH ARTICLE OPEN ACCESS