Impact of conjugated polymer addition on the properties of paraffin–asphaltene blends for heat storage applications: Insight from computer modeling and experiment
Adding carbon nanoparticles into organic phase change materials (PCMs) such as paraffins is a common way to enhance its thermal conductivity and to improve the efficiency of the heat storage devices. However, sedimentation stability of such blends can be low due to aggregation of aromatic carbon nanoparticles in the aliphatic paraffin environment. In this paper we explore whether this important issue can be resolved by introduction of a polymer agent such as poly(3-hexylthiophene) (P3HT) into the paraffin-nanoparticle blends: P3HT could ensure the compatibility of aromatic carbon nanoparticles with aliphatic paraffin chains. We employed a combination of experimental and computational approaches to determine the impact of P3HT addition on the properties of organic PCMs composed of paraffin and carbon nanoparticles (asphaltenes). Our findings clearly show an increase in the sedimentation stability of paraffinasphaltene blends, when P3HT is added through a decrease in average size of asphaltene aggregates as well as in an increase of the blends’ viscosity. We also witness the appearance of the yield strength and gel-like behavior of the mixtures. At the same time, presence of P3HT in the blends has almost no effect on their thermophysical properties. This implies that all properties of the blends, which are critical for heat storage applications, are well preserved. Thus, we demonstrated that adding polyalkylthiophenes to paraffin-asphaltene mixtures led to significant improvement in the performance characteristics of these systems. Therefore, the polymer additives can serve as promising compatibilizers for organic PCMs composed of paraffins and asphaltenes
and other types of carbon nanoparticles.