Progress in Organic Coatings 62 (2008) 32–39 Development of novel waterborne poly(1-naphthylamine)/ poly(vinylalcohol)–resorcinol formaldehyde-cured corrosion resistant composite coatings Sharif Ahmad ∗ , S.M. Ashraf, Ufana Riaz, Sarvat Zafar Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025, India Received 25 February 2007; received in revised form 9 September 2007; accepted 11 September 2007 Abstract Advancements in the field of corrosion protective coatings have headed towards the utilization of conducting polymer-based blends and composites for the formulation of corrosive protective paints and coatings. With the aim to develop an ecofriendly waterborne conducting polymer-based protec- tive coating material, corrosion protective behavior of waterborne resorcinol formaldehyde (RF)-cured composite coatings of poly(1-naphthylamine) (PNA)/poly(vinylalcohol) (PVA) was investigated on mild steel (MS). The corrosion protective performance was evaluated by physicochemical, physicomechanical, corrosion protective efficiency and resistance in acid, alkaline and saline media by open circuit potential (OCP) measurements. The morphologies of coated, uncoated as well as corroded samples were analyzed by SEM technique. Superior corrosion protective performance was observed which was compared to the reported solvent-based conductive polymer coatings in different corrosive media. © 2007 Elsevier B.V. All rights reserved. Keywords: Waterborne composite; Corrosion; Open circuit potential; Coating; Poly(1-naphthylamine); SEM; Nanoparticles 1. Introduction Due to the imposition of the legislative restrictions on the emission of the volatile organic compounds (VOC), water- borne coatings are finding more and more importance among the various high performance solvent-based industrial coatings. Water, as a solvent, has the advantages of being non-toxic and non-flammable. Waterborne coating formulations have recently gained much popularity for ambient cure coating applications because of their potential benefits. They represent a range of characteristics, which in some cases, are not exhibited by solvent-borne paints and coatings [1–5]. However, waterborne paints are found to be less resistant to the corrosion process gen- erated by water, ions and oxygen permeation and are more prone to biological attack [2,6–9]. Standard test methods, which are suitable for organic paint coatings fail in case of waterborne sys- tems. Salt spray and humidity chamber tests show poor results for certain waterborne paint/coatings, if tested soon after their formation [10]. ∗ Corresponding author. E-mail address: sharifahmad jmi@yahoo.co.in (S. Ahmad). Moreover, traditional anti-corrosive paints contain lead and hexavalent chromium compounds as toxic pigments which con- taminate the environment and represent a risk to human health. Many non-toxic compounds have been suggested as possible replacements for chromates and lead compounds. Recently, the potential application of conducting polymers as corrosion inhibitors has gained momentum owing to their anti-corrosive performance. A number of studies on corrosion inhibition involving conducting polymers were reported in the mid 1990s with an upsurge of interest in the past few years. Deberry [11] in 1985 first reported that doped polyaniline performed well as a corrosion resistance coating on ASTM430 stainless steel. Many of these studies have concentrated on polyani- line applied as a solution or as dispersion on iron or steel followed by epoxy top coat to protect polyaniline containing phase and provide additional barrier against corrosive agents [12–15]. Other approaches include dissolving polyaniline in N-methylpyrrolidone [16], DMSO [17] or blending it with epoxy resin using alkylphenyl cosolvent [18]. Some com- mercial formulations such as VERSICON [19–21], PANDA [13,19,21] and CORREPAIR [12], which have lead to, reduced rates of corrosion on various steels. The use of substituted polyaniline such as poly(anisidine), poly(methoxyaniline) have 0300-9440/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.porgcoat.2007.09.014