Chemical Agent Resistant Coatings (CARCs) have long been used to protect infrastructure, vehicles and equipment from chemical agents such as mustard gas and nerve agents (saran or VX) in combat zones. CARCs are designed to slow the absorption of chemical agents into the coating, protecting the material underneath and buying time for decontamination. Chemically resistant paints are traditionally made by adding higher loads of the same pigments and extenders that are added to commercially available paints. This higher loading delays absorption of the chemical agent, but does not provide complete lasting protection. Exposed surfaces must be thoroughly cleaned or bleached. In cases where the surfaces have been extensively contaminated, the asset may need to be stripped to remove traces of chemical agents that have been absorbed into the coating; often assets are simply demilitarized due to the expense of stripping and recoating. This decontamination process is both time-consuming and expensive. Battelle has developed a new smart coating that sheds and decontaminates chemical agents to better protect infrastructure and combat equipment.
Battelle develops smart, functional surfaces to solve specific problems for our clients. The CARC project built on lessons learned in developing laundry additives that would remain on clothes after the wash cycle to provide stain repellence. We ultimately developed a hydrophobic (water repelling) molecule that used ionic interaction with the fabric to resist water flushing during the rinse. A similar approach was used to develop a paint additive that would interact strongly with the underlying material while repelling the chemical agent. Because most chemical agents are hydrophilic, we developed a hydrophobic coating so that the agent will be shed in the field and not be absorbed. A functional silica group actively decontaminates the surface by reacting with any remaining traces of chemical agent and breaking it down into harmless compounds. The material can be added to any paint or coating in the form of a powder. The bonding and functional groups can be customized to the specific application.
The new CARC has the potential to significantly reduce cleaning and paint costs for the military. Rather than going through expensive decontamination or demilitarizing assets, field personnel can rely on the paint to decontaminate itself. The additive is non-photocatalytic, so it will not degrade the coating over time with exposure to light. This allows the CARC to provide long-lasting protection to equipment and infrastructure in combat zones. Similar surface decontamination technology could one day be applied to develop other protective surfaces for the consumer and industrial space, such as industrial paints that react with toxins and carcinogens to break them down into less harmful substances. Surface decontamination could also be used in fabrics and equipment used by workers who may be exposed to toxic or carcinogenic substances.