Evaluation of carbon nanotubes-phthalocyanine composite coatings as thermal camouflage materials

Abstract

This project designs a new camouflage material that operates in the infrared (IR) region. The project reports on the synthesis and characterization of an IR camouflage composite coating made of carbon nanotubes (CNTs) and phthalocyanine (Pc). The synthesized coating was drop-cast separately on paper, poly(ethylene terephthalate) (PET) fibre, nylon fibre and glass fibre substrates. Thermal degradation studies on the four substrates revealed that paper and glass fibre are thermally stable substrates for the coating curing process, with satisfactory coating coverage. This project also compares drop-casting and gel spreading methods to coat paper substrates. The drop-cast method demonstrated to be a facile method which produced excellent substrate coverage. Comparison among 1 wt% to 5 wt% CNT coatings revealed 2 wt% CNT coating to have better coating quality. The coating increased thermal stability of paper from 250 °C to 350 °C. Absorbance in ultraviolet, visible, near-infrared regions was also significantly increased, with a maximum absorbance for the 2 wt% CNT coating. Thermal emissivity and conductivity of the coating measured did not show conclusive improvement due to uncertainties such as curvature of the paper substrates used. Although the coating achieved the expected absorbance spectrum in the near IR region, optimization on the coating coverage and uniformity on the substrate has to been done. The project recommends further exploration of additional methods of coating and usage of alternative networking-forming polymers.