Plasma surface energy properties

Contact angles were measured on plasma polymers deposited from numerous hydrocarbon monomers of different structure containing triple bond, olefinic double bonds, aromatic and aliphatic structures. The results of contact angle measurements and evaluated surface energy properties for these polymers are summarized in Table II, column A. The data for plasma polymers from acetylene, ethylene, and hexane indicate that monomer unsaturation does not change substantially the dispersion component but increases the polar component to a considerable extent as in the case of acetylene. This, undoubtedly, is due to the high concentration of radicals in PP-AC and resulting rapid formation of carbonyls and... 

The data for plasma polymers deposited from the aliphatic monomers cyclohexane and hexane indicate that both structures (cyclic and linear) produce polymers of similar surface energy properties. 

Table III. Effect of Vacuum Thermal Treatment for 30 min. at 800 C on Contact Angles and Surface Energy Properties of Plasma Polymer Films Deposited from Organosilicon Monomers.

The results prove that the surface energy properties of plasma polymer films can be modified by using an appropriate thermal posttreatment process which appeared to be particularly useful for the production of strongly adherent protective coatings for metals. 

In general, plasma polymers are amorphous and highly crosslinked materials of irregular chemical structure.Differences in the structures of plasma and conventional polymers should also be reflected in their surface energy properties. 

Table IV exemplifies the surface energy properties of some plasma polymers (data from Tables I and II, columns A) and their conventional counterparts. The surface energy components for conventional polymers were calculated from contact angle data of water/methylene iodide system reported by Shafrin et al. There are also specified the densities of plasma polymers and conventional amorphous counterparts, respectively. The data in Table IV clearly indicate that plasma polymers have higher surface energy as compared to their conventional counterparts. This apparently results from the increased dispersion and polar (except PP-VDC) components of their surface energy. The increase in y noted...

Table IV. Surface Energy Properties and Densities of Plasma Polymers and Their Conventional Counterparts. 

In the process of plasma polymerization, a highly crosslinked polymer is deposited on the surface The deposited plasma polymer changes the surface properties of the substrate dramatically. It modifies the surface of powders in terms of surface energy, functional groups, wettability, interaction with polymers, and dispersion... 

Plasma treatment is useful to activate the surface of a certain material. The treatment enhances the adhesion property. Basically, surface activation effects the introduction of chemical functionalities on the polymer surface in order to increase its surface energy. 

The main objective of this article is to summarize the work performed at the Max-Planck-Institute for Plasma Physics in Garching over the past few years relevant to plasma-surface interaction processes in the system hydrogen and carbon. This includes a short review of the properties of amorphous, hydrogenated carbon layers, further on abbreviated as a-C H, determination of reaction probabilities of reactive species such as atomic hydrogen and methyl radicals, and investigation of the simultaneous interaction of these species and low-energy ions with hydrocarbon surfaces. The reviewed ma-... 

Polymer surface modifications are omnipresent in applications where the surface properties of materials with favorable bulk properties are insufficient. By altering the surface characteristics using physical or chemical modification the desired surface properties may be achieved. Such treatments are required e.g. to enhance printability of films, the adhesion of paints, metal or other coatings, biocompatibility, protein resistances/reduced biofouling, etc. The diverse approaches met in practice include, among others, wet chemical and gas phase chemistry, plasma or corona, UV/ozone and flame treatments. In most cases surface chemical modification reactions take place that alter the surface energy in a desired way. For example,... 

Using these fundamental reactions of plasma, many polymer properties such as optical reflection, adhesion, friction coefficient, surface energy (wettability and water repellancy), permeability, and biocompatibility of conventional polymers can be controlled by the appropriate application of a plasma treatment. A typical industrial and large-scale application of this technique is the surface treatment of automobile bumpers. The advantage of this technique is the fact that plasma treatment usually... 

PE represents one of the simplest food packaging polymers. PE with different densities, water vapor transmission rates, gas transmission rates, and mechanical properties, e.g., tensile strengths, is commercially available. This variety provides food manufacturers with ability to choose the optimmn packaging material for their needs [45]. The surface of PE is necessary due to its low polarity and low surface energy to modify by low-temperature discharge plasma in air [3-6]. PE surfaces modified by CO2, H2O, and CO2/H2O plasma have been also characterized [46]. 

To enhance the adhesive strength, the surface properties of substrate are very important. The surface treatments are often used to enhance the adhesive strength between the coating and the substrate, as well as to enhance the surface energy of substrate - improving wettability of coating. If adhesive problem occurs, check out the surface treatment processes such as flame, plasma, or corona. Corona treatment does not persist permanently, therefore it should be done in-line, the corona is often applied directly before the coating station. 

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