Abstract:
The threat of chemical warfare agent (CWA) release poses risks to exposure from contact with vehicle and building surfaces that are susceptible to remain contaminated for extended duration after a release event. Current decontamination approaches require the application of the caustic and corrosive solutions which, in addition to decomposing the toxic contaminant, also contribute to the degradation of the object being decontaminated and present their own inherent health risks. Often material surfaces are covered in polymeric coatings, paint, that provides a convenient substrate into which novel reactive additives can be incorporated to impart automatic decontamination capability to their surface. A self-decontaminating coating has the capability to automatically facilitate the decomposition of toxic contaminants on its surface, thereby reducing the risk of exposure and the reliance on aggressive decontamination solutions. Reactive molecules C60 and polyoxometalate (POM) have exhibited capability to impart self-decontaminating behavior to a coating surface; however, these additives also impart negative properties onto the coating such as roughness and reduced physical characteristics that arise from intermolecular incompatibilities between additive and polymer matrix. Herein, amphiphilic modifications of reactive additives were performed to improve the incorporation into polymer coating systems. Further, POM additives exhibiting a range of amphiphilic character were synthesized to investigate the role of additive composition in dispersion in a polymer matrix. The synthetically modified products were thoroughly characterized to elucidate their intramolecular binding. Amphiphilic modification was investigated as it has the potential to cause the additive to automatically orient at the polymer-air interface, or surface segregate. The amphiphilic additives were incorporated into control polymer solutions and their surface and bulk properties were comprehensively analyzed. Amphiphilic modification resulted in the improved incorporation of POM and the surface segregation of C60 in polyurethane polymers. Upon incorporation of amphiphilic additives into polyurethane coatings, surface reactivity against CWA simulants in simulated environmental conditions confirmed imparted self-decontamination. The mechanism of reaction for the amphiphilic C60 was determined to be a photocatalytic oxidation upon challenge with chemical warfare agent simulants.
