Nanomaterial additives for self-repair coatings

Current corrosion protection for the US Navy is often provided by Chromium based compounds which are considered hazardous and potential carcinogens. Exposure can occur during coating operations, and release is highly probable in sea water applications. A suitable alternative is therefore needed, but will have to closely match the performance of the Chromate Conversion Coatings (CCCs) in terms of damage responsiveness without the adverse environmental and health effects. An additional concern in ship coatings are fouling of the paint surface which can result in decreased speed and increased fuel consumption. Building upon ongoing work on polyurethane nanocomposite coatings at NEI Corporation, we propose to develop a new class of easily applied damage responsive (i.e. self-repairing), antifouling polymer nanocomposite coatings for corrosion protection of steel for naval ships. The proposed multifunctional water-based urethane coatings will contain a dispersion of conducting polymer-ion complexes, semiconducting nanoparticles, and hydrophobic nanophase domains. Active corrosion repair will be accomplished by polymer-ion complexes in the matrix phase of the nanocomposite. Semiconducting nanoparticles and polymers will provide anodic protection and high resistance of electron flow in galvanic corrosion cells that are formed due to damage to the coating. The nanoparticles will also provide anti-fouling capability to the system in concert with the hydrophobic nanophase domains. NEI’s damage responsive, anti-fouling polymer nanocomposite coatings will enable the Navy to safely and economically protect metal substrates from corrosion and fouling in underwater applications. The formulation developed in this program will be incorporated in commercial coating formulations to enhance anti-fouling capability and impart self-repair characteristicsBENEFITS: The maintenance costs associated with corrosion for the DOD is estimated at $10 to $20 Billion/year. Additionally, the Navy spends $100 million annually for hull cleaning, ablative anti-fouling coatings, repainting, and other issues associated with fouling. Add to this the estimated 30% reduction in fuel efficiency due to fouling. The proposed damage responsive corrosion protection/ anti-fouling coatings could aid in offsetting these high costs for conducting naval operations.