Repetitively pulsed atmospheric pressure discharge treatment of rough polymer surfaces: II. Treatment of micro-beads in He/NH₃/H₂O and He/O₂/H₂O mixtures

Abstract

Plasmas are increasingly being used to functionalize the surface of polymers having complex shapes for biomedical applications such as tissue scaffolds and drug delivering micro-beads. The functionalization often requires affixation of amine (NH 2 ) or O-containing groups. In this paper, results are discussed from a two-dimensional computational investigation of the atmospheric pressure plasma functionalization of non-planar and porous surfaces of polypropylene with NH x and O-containing groups. For the former, the discharge is sustained in He/NH 3 /H 2 O mixtures in a dielectric barrier-corona configuration. Significant microscopic non-uniformities arise due to competing pathways for reactive gas phase radicals such as OH and NH 2 , and on the surface by the availability of OH to initiate amine attachment. The treatment of inside surfaces of porous polymer micro-beads placed on an electrode is particularly sensitive to view angles to the discharge and pore size, and is ultimately controlled by the relative rates of radical transport and surface reactions deep into the pores. The functionalization of micro-beads suspended in He/O 2 /H 2 O discharges is rapid with comparable treatment of the outer and interior surfaces, but varies with the location of the micro-bead in the discharge volume.

Nitrogen plasma functionalization of low density polyethylene

“…In this previous work we also found that NH* species are preferentially formed in the DBD and, to a lesser extent, in MW ammonia-containing plasmas, while N 2 * and N 2 + species form in the DBD and, preferentially, MW nitrogen plasmas. In agreement with previous works [48,49], these findings indicate that NH* species, majority in the DBD Ar + NH 3 plasmas, are more efficient than other nitrogen species for the nitrogen functionalization of polymers. The efficiency of neutral NH* species for this purpose is further supported by the results here with the beams of neutral species.…”

“…A significant difference between DBD atmospheric plasmas and low pressure MW plasmas is that, in the former case, neutral active species are more abundant than in the latter. The opposite happens with regard to the concentration of ionized species [46][47][48][49]. This has been effectively verified with our experimental setups in previous characterization studies by optical emission spectroscopy (OES) [22].…”

Influence of Water Vapor Addition on the Surface Modification of Polyethylene in an Argon Dielectric Barrier Discharge

“…Moisture content in plasmas for surface modification has often been viewed as an impurity in low pressure systems and more particularly when dealing with open‐atmosphere plasma sources. However, very few studies have intentionally used water vapor as a reactive gas for plasma surface modification, and when used, only in low concentrations .…”

Nitrogen grafting onto polycarprolactone by a simple surface modification with atmospheric pressure glow discharge (Ar-APGD) and promoted neonatal human fibroblast growth

“…6,7,9,15,16,[24][25][26][27] Those are grafting of hydroxyl group, carboxyl group and amine groups. The modified surface showed increased hydrophilicity, enhanced wettability to the culture medium, promoted cellular responses such as attachment and proliferation.…”

“…corrosive ammonia with inert gases or nitrogen with inert gases, or special post-solution treatments. 6,14,15 Use of ammonia gas requires special corrosion protection equipment design and environmental treatment units. According to optical emission study of dielectric barrier discharge (DBD) type atmospheric pressure plasma, the intensity of nitrogen emission depended on argon flow rate owing to ambient atmosphere.…”