Journal of Coating Science and Technology, 2015, 2, 20-27 20 E-ISSN: 2369-3355/15 © 2015 Lifescience Global Journal of Coating Science and Technology http://www.lifescienceglobal.com/journals/journal-of-coating-science-and-technology Processing, Adhesion and Corrosion-inhibiting Properties of Poly[2-methoxy-5-(2’-ethylhexyloxy)-1,4-phenylene vinylene], (MEH-PPV) on Aerospace Aluminum Alloys Peter Zarras 1,* , Diane Buhrmaster 2 , John D. Stenger-Smith 1 , Cindy Webber 1 , Nicole Anderson 1 , Paul A. Goodman 1 , and Matthew C. Davis 1 1 Naval Air Warfare Center Weapons Division (NAWCWD), Polymer Science & Engineering Branch (Code 4L4200D), 1900 N. Knox Road (Stop 6303), China Lake, CA 93555-6106, USA 2 Air Force Research Laboratory/Logistics Systems Support Branch Coatings Technology Integration Office, UDRI Contactor Support, Bldg 1661, Rm C-110, Wright-Patterson AFB, University of Dayton Research Institute, Nonstructural Materials Division, 300 College Park, Dayton, OH 45469-0054, USA Abstract: Researchers at the Naval Air Warfare Center Weapons Division (NAWCWD) and Wright- Patterson Air Force Base (WPAFB) investigated poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene], (MEH-PPV) for its potential corrosion-inhibition properties on aerospace aluminum alloy AA2024- T3. Solution processing of the polymer, as well as adhesion testing and accelerated weathering tests, were performed on MEH-PPV full military aerospace coatings. Wet and dry tape adhesion testing, as well as pencil hardness, impact flexibility, and pneumatic adhesion tensile test instrument (PATTI) testing was used to demonstrate the adhesion performance of MEH-PPV on aluminum substrates. The results showed that MEH-PPV had acceptable adhesion characteristics when compared to hexavalent chromium (Cr(VI)) based coatings in all of these tests. Accelerated weathering analysis was performed on MEH-PPV coatings to determine their corrosion protection and weathering resistance capabilities. These tests included neutral salt spray (NSS) exposure and xenon-arc lamp testing. The results showed that while MEH-PPV does not exhibit significant color change after 500 hours of xenon arc lamp exposure, the polymer has poor corrosion protection performance under aggressive salt environments. Received on 23-12-2014 Accepted on 13-04-2015 Published on 24-04-2015 Keywords: Poly[2-methoxy-5- (2’-ethylhexyloxy)-1,4- phenylene vinylene](MEH- PPV), hexavalent chromium (Cr(VI)), chromate conversion coating (CCC), adhesion testing, pencil hardness, impact flexibility, accelerated weathering testing. DOI: http://dx.doi.org/10.6000/2369-3355.2015.02.01.4 1. INTRODUCTION * The United States military relies on multi-component protective coating systems to maintain the operational readiness of military aircraft. Current high-performance aerospace coating systems consist of three layers, a pretreatment, primer, and topcoat. Coatings for the military center on the use of hexavalent chromium (Cr(VI)) in both the pretreatment and primer layers. The current aerospace coating has been developed over many years to meet the strenuous challenges of corrosion, adhesion, and weathering encountered by military platforms [1, 2]. Chromate conversion coatings (CCC’s) and Cr(VI) primers are effective at inhibiting corrosion because they can provide * NAWCWD, Polymer Science & Engineering Branch (Code 4L4200D), 1900 N. Knox Road (Stop 6303), China Lake, CA 93555-6106, USA; Tel: 1-760-939-1396; Fax: 1-760-939-1617; E-mail: peter.zarras@navy.mil corrosion-inhibition of metals and alloys via a "self-healing" mechanism. The CCCs and Cr(VI) primers act as a reservoir of mobile Cr(VI) that is capable of migrating to defects and inhibiting further corrosion by forming passivating layers on the metal surface [3-6]. However, Cr(VI) is a known carcinogen and toxin to humans and the environment [7]. Over the past 25 years, published evidence that electro active polymers (EAPs), such as polyaniline (PANI), can inhibit corrosion has come from the pioneering work of Mengoli [8], DeBerry [9] and MacDiarmid [10]. Mengoli showed that EAP coatings deposited onto iron anodes by electro-polymerization of aniline resulted in an adherent and corrosion inhibiting film. Further work by DeBerry showed that PANI electrochemically deposited onto stainless steel in sulfuric acid solution changed the corrosion behavior of the stainless steel substrate. This work demonstrated that the PANI film provided anodic protection, thus, maintaining a