Plasma parameters effects on the properties, aging and stability behaviors of allylamine plasma coated ultra-high molecular weight polyethylene (UHMWPE) films

Abstract

In this work, a dielectric barrier discharge (DBD) operated at medium to atmospheric pressure has been used for the deposition of thin polyallylamine (PAA) films on ultra-high molecular weight polyethylene (UHMWPE) substrates. The effect of treatment time (1–5min), discharge power (5.7–24.0W), monomer concentration (1–2g/h) and pressure (10–100kPa) on the films properties, aging and stability behaviors have been investigated. The used characterization techniques are X-ray photoelectron spectroscopy, water contact angle and optical reflectance spectroscopy.In this paper, it is shown that plasma treatment time does not affect the coatings chemistry; whereas plasma power, monomer concentration and pressure control the coatings properties. It is also shown that the deposition rate of the deposited films changes with varying W/FM values. At low W/FM values, high deposition rates of up to 2nm/s are observed.Plasma treatments were also characterized by their amino efficiency ([NH2]/[C] in %) and amino selectivity ([NH2]/[N] in %). Depending on the used parameters, these varied between 12.3% and 20% and between 71.2% and 91.1%, respectively.For the aging study, coatings that preserved most of their hydrophilicity were obtained at power ≤11.3W, monomer concentration ≥1.5g/h and pressure ≥50kPa.For the stability study, coatings that showed the highest [N] (%) and lowest percentage of thickness decrease were obtained at ≤2min, 24.0W, 1g/h and pressure ≤50kPa.One can therefore control the deposition rate as well as the properties, aging and stability behaviors of the deposited coating by carefully choosing the plasma parameters.