ABSTRACT:Here we present how the surface and some filtration properties of PVC microfiltration membranes are affected by controlled and well-defined modification by ionplasma treatment in the kinetic region of the high voltage (HVGD) or normal glow discharge (NGD) in air. The surface energy and work of adhesion of the samples were calculated from the contact angle with both polar (H 2 O) and nonpolar (CH 2 I 2 ) liquid measurement data. The surface morphology was observed by SEM and the surface chemical composition was analyzed by ESCA. The trans-membrane water flux, the average pore size, and the pore-size distribution as well as the "bubble point" were used to control the effect of the ion-plasma treatment on the filtration properties of the PVC microfiltration membranes. Two characteristic regions of the ion-plasma treatment in air were found in our experiments where the surface properties and filtration characteristics of the membranes are extremely changed: at a pressure of 10 -15 Pa in the region of the HVGD and at a pressure of 100 -120 Pa in the region of the NGD. It was shown that the ion-plasma treatment in air is an effective technological method for regulation of some important surface and filtration properties of PVC microfiltration membranes.
Corona-treated wood flour was evaluated as a filler for NBR (nitrile butadiene rubber) compounds by studying its influence on their cure characteristics and mechanical properties. The different operating conditions of the corona treatment, such as voltage and duration, which led to different degrees of surface etching, were observed by means of electron microscopy. Accumulation of different oxygen-containing groups on the wood flour particles' surface was confirmed by means of ESCA. Wood flour-filled materials were thus obtained with varying final properties.The cure characteristics, mechanical parameters, and water adsorption of the composites were estimated to determine an optimum level of the wood flour surface modification. The corona treatment of the wood flour renders it into a semiactive filler.
Assuming that the existence of an ion-flow in the plasma volume could strength the surface modifying effect, including its durability, a parallel plate reactor in reactive ion etching mode was employed to obtain surface modified PDMS with improved cellular interaction. The discharge power was varied at 100, 1200, and 2500 W to ensure varied ion-flow density. The changes in the surface topography were observed by SEM and AFM, and the surface roughness was characterized by both: mean roughness, R a , and root-mean-square, R q . Time dependent water contact angle measurements were performed to control the durability of the hydrophilizing effect. Anisotropic etching, accompanied with decrease of the PDMS surface roughness, was observed up to discharge power of 1200 W that turns in intense isotropic one, accompanied with a sharp increase of the surface roughness over 1200 W, most probably because of arise of reverse sputtered neutrals diffracting the main plasma Ar þ flow. Human fibroblasts were applied as an in vitro model to learn more about the initial cellular interaction of the modified surfaces and to identify the optimal treatment conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.