Synthesis and infrared property of polyaniline/phase-change nanocapsule composite

A composite of polyaniline (PANI) and nanoencapsulated phase-change material (PCM) with polystyrene (PS) as the shell and n-octadecane as the core was synthesized using the ultrasonic technique assisted by in situ polymerization. The composite's morphology, structure, and thermal properties were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results showed that the surface of the PCM nanocapsules was covered with PANI. The phase-change temperature of the nanocapsules of PCM and the composite was slightly lower than that of n-octadecane. Their latent heat was less than the calculated value based on the mass ratio of n-octadecane measured by TGA. The infrared emission properties of PANI, the phase-change nanocapsule, and the composite were studied using an IR-II infrared emissivity instrument and an infrared camera. It was found that the infrared emissivity of the composite was appreciably higher than that of PANI. However, the composite showed lower temperature than the PANI when observed by infrared camera with the increasing ambient temperature around the n-octadecane phase-change temperature. This occurred because the phase-change material in the composite absorbs so much heat that infrared emissions were obviously decreased when the ambient temperature rose.