Polyacrylic acid thin films have been deposited by an original and fast technique to grow organic coatings: a pulsed‐arc atmospheric pressure plasma jet. Liquid acrylic acid was introduced in the nitrogen plasma jet and OES was used to measure the fragmentation of the precursor. The films were characterized by XPS, FTIR and SEM analyses before and after soaking in water. The water stability was also investigated by weight loss measurement. A high retention of carboxylic moieties, i.e. functional groups of the monomer has been observed for coatings deposited under mild conditions for the jet (low frequency and high jet speed). These films have been used for cell adhesion using human ovarian carcinoma cells (NIH:OVCAR‐3). Good results have been obtained depending on the plasma parameters, showing that atmospheric pressure plasma jet is a promising technique to grow organic thin films for biomedical applications.magnified image

No abstract

Water stable plasma polymerized acrylic acid/methylene-bis-acrylamide (ppAA/MBA) thin films have been deposited with an atmospheric pressure air plasma jet, a fast technique to grow organic thin films. To increase the stability of the coatings, a cross-linking agent (MBA) was added to the precursor (AA), which was introduced with a home-made spraying system. The jet speed and pulse frequency of the discharge were investigated regarding the properties of the coatings. Two types of materials were obtained: in low energy conditions (high jet speed and low frequency) the films presented a water-soluble part with a certain organized structure. When more energy is supplied to the growing films, a more polymerized material with a more amorphous structure is obtained. Increasing the energy further leads to the deposition of a more crosslinked film with a better stability to water. In optimized conditions, no weight loss and no significant chemical change were noticed after soaking in water.

http://www.interscience.wiley.com/International audienceSurface activation of polymers by atmospheric pressure plasma is an economically important process for bonding technologies. Although most of the studies are focused on the modification of the surface chemistry, this study investigates the modification of the topmost surface and the deeper layers of a polyamide-6 sheet treated by an open-air atmospheric plasma jet system. The plasma jet used in this study is a unique combination of highly reactive species (e.g. O8, 8OH. . .) and a high temperature gas estimated (from 600–1 000 K) which leads to surface functionalization,amorphization and polymorphism modification. The results have shown that an amorphization of the polyamide occurs on the top surface. Moreover, a crystallization of the amorphous phase in the a form was also highlighted in the depth of the material

International audienceA pulsed-arc atmospheric pressure air plasma jet has been used to depositplasma polymerized acrylic acid/methylene-bis-acrylamide (ppAA/MBA) organic thinfilms. Optical emission spectroscopy has been performed to investigate the reactivity of theplasma and the dissociation of the precursor as a function of the pulse frequency anddistance from the nozzle. An estimation of the OH rotational temperature, which is anindicator of the plasma gas temperature, has also been performed. By heating the substrateduring deposition, it was possible to improve to a great extent the stability to water of thecoatings. Stable ppAA/MBA films have been obtained with an air plasma over a largerange of pulsed frequencies (from 15 to 25 kHz) when the substrate was heated to 200° C.The composition of these coatings was investigated by FTIR and different amide/acidratios were obtained, showing the possibility to grow stable films with different functionalgroups by adjusting the deposition parameters

The latest trends in the automotive industry show a shift towards more lightweight, robust vehicles powered by electric energy. Light weighting can be achieved through the use of carbon‐reinforced composite materials or light metals, such as aluminum, and by using adhesives for bonding instead of rivets and bolts. In this paper, results from the characterization of plasma‐treated polypropylene using water contact angle goniometry, X‐ray photoelectron spectroscopy, and attenuated total reflectance Fourier‐transform infrared spectroscopy are presented, showing the functionalization of the surface with chemical groups originating in the plasma phase. The improved adhesion to a hot melt adhesive is discussed and linked to an industrial headlamp application. Other case studies presented involve the plasma treatment of thermoplastic elastomers for car doors, the surface modification of semi‐trailer panels, and the deposition of plasma‐derived nanocoatings on aluminum substrates to promote corrosion resistance.

No abstract

Long term reliability and performance of printed circuit boards (PCBs) are strongly affected by the presence of surface contaminants from the manufacturing and assembly processes. Flux and solder residue, dust particles, oils and greases are often found on the assembled boards and can inhibit the successful application of conformal coatings that are used to protect the electronic components. Surface contaminants can cause coating delamination, dendritic growth, electromigration, corrosion and result in compromised coatings. In the first part of this paper, the fundamental mechanism of plasma-induced removal of organic contaminants from PCBs will be presented. While vacuum based plasmas are considered the traditional solvent-free technology for surface cleaning, a new approach involving air plasma operating under atmospheric pressure conditions is gaining interest due to its adaptability for industrial inline processing. The low concentration of oxygen that is available in the plasma gas is effective in vaporizing organic contaminants leaving behind a clean surface. Additionally, atmospheric plasma processes focusing on the development of functional nanocoatings on PCBs have been investigated. These plasma-enhanced chemical vapor deposition (PECVD) processes involve the delivery and vaporization of small volumes of solvent-free precursors that react with the plasma to form thin coatings on polymer substrates. Depending on the chemical structure of the precursor used, adhesion promoting, water repellant or electrical barrier coatings of 30–100nm thickness can be deposited. These protective functional coatings do not require any curing or special handling and no chemical waste is generated. The latest developments in atmospheric pressure PECVD for electronics protection will be presented in the second part of the paper. Besides the improvement of device performance and reliability, the application of PECVD has the potential to replace chemical substances such as primers known to have harmful impact on human health and the environment.