The stability of poly(3‐hexylthiophene) (P3HT) helical structure has been investigated in vacuo and in amorphous polymer surrounding via molecular dynamics‐based simulations at temperatures below and above the P3HT melting point. The results show that the helical chain remains stable at room temperature both in vacuo and in amorphous surrounding, and promptly loses its structure at elevated temperatures. However, the amorphous surrounding inhibits the destruction of the helix at higher temperatures. In addition, it is shown that the electrostatic interactions do not significantly affect the stability of the helical structure. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 2448–2456

Deep eutectic solvents (DESs) are one of the most rapidly evolving types of solvents, appearing in a broad range of applications, such as nanotechnology, electrochemistry, biomass transformation, pharmaceuticals, membrane technology, biocomposite development, modern 3D-printing, and many others. The range of their applicability continues to expand, which demands the development of new DESs with improved properties. To do so requires an understanding of the fundamental relationship between the structure and properties of DESs. Computer simulation and machine learning techniques provide a fruitful approach as they can predict and reveal physical mechanisms and readily be linked to experiments. This review is devoted to the computational research of DESs and describes technical features of DES simulations and the corresponding perspectives on various DES applications. The aim is to demonstrate the current frontiers of computational research of DESs and discuss future perspectives.

We put forward chemically modified asphaltenes, polycyclic aromatic byproducts of deep oil refining, for use as novel low-cost acceptor materials for bulk heterojunction (BHJ) solar cells. The electronic properties of asphaltenes with varying chemical structures are studied by density functional theory (DFT), while the morphology of DFTselected carboxyl-containing asphaltenes mixed with poly(3-hexylthiophene) (P3HT) as a model polymer-donor is investigated by means of all-atom molecular dynamics (MD) simulations. DFT calculations show that the chemical modification of asphaltenes with carboxyl groups enables their energy levels to be fine-tuned, thereby obtaining the desirable energy difference between the lowest unoccupied molecular orbitals of the acceptor and donor materials for efficient charge transfer. MD simulations reveal the heterophase morphology of the P3HT/asphaltene mixture, as well as the formation of extended stacks of asphaltenes via π−π stacking between their polyaromatic cores. Overall, from both the electronic and morphological standpoints, carboxyl-containing asphaltenes do indeed represent a potential low-cost acceptor for BHJ solar cells.

Deep eutectic solvents (DESs) are one of the most rapidly evolving types of solvents, appearing in a broad range of applications such as nanotechnology, electrochemistry, biomass transformation, pharmaceuticals, membrane technology, biocomposite development, modern 3D-printing, and many others. The range of their applicability continues to expand, which demands the development of new DESs with improved properties. To do so requires an understanding of the fundamental relationship between the structure and properties of DESs. Computer simulation and machine learning techniques provide a fruitful approach as they can provide predictions, reveal physical mechanisms and readily be linked to experiments. This review is devoted to the computational research of DESs and describes technical features of DES simulations and the corresponding perspectives on various DES applications. The aim is to demonstrate the current frontiers of computational research of DESs and discuss future perspectives.

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 paraffin-asphaltene 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.

The problem of developing conducting molecular wires has recently received increased attention. We present the results of molecular dynamics simulations aimed at investigating the selforganization process of conjugated 2,5-dialkoxy-phenylene-thiophenebased oligomers (TBT) on a monolayer graphene over a wide range of temperatures. The local structural characteristics of the TBT oligomers and the macroscopic characteristics of their aggregates are investigated. It is shown that electrostatic interactions significantly affect the local structural characteristics of the molecules resulting in liquid-crystalline type of ordering of the oligomers on graphene. It is also found that the length of the oligomers assures the structural stability of ordered aggregates even at elevated temperatures.

Further development and commercialization of bulk heterojunction (BHJ) solar cells require the search for novel low-cost materials. The present study addresses the relations between the asphaltenes’ chemical structure and the morphology of the poly(3-hexylthiohene) (P3HT)/asphaltene blends as potential materials for the design of BHJ solar cells. By means of all-atom molecular dynamics simulations, the formation of heterophase morphology is observed for the P3HT-based blends with carboxyl-containing asphaltenes, as well as the aggregation of the asphaltenes into highly ordered stacks. Although the π–π interactions between the polyaromatic cores of the asphaltenes in solutions are sufficient for the molecules to aggregate into ordered stacks, in a blend with a conjugated polymer, additional stabilizing factors are required, such as hydrogen bonding between carboxyl groups. It is found that the asphaltenes’ aliphatic side groups may improve significantly the miscibility between the polymer and the asphaltenes, thereby preventing the formation of heterophase morphology. The results also demonstrate that the carboxyl-containing asphaltenes/P3HT ratio should be at least 1:1, as a decrease in concentration of the asphaltenes leads to the folding of the polymer chains, lower ordering in the polymer phase and the destruction of the interpenetrating 3D structure formed by P3HT and the asphaltene phases. Overall, the results of the present study for the first time reveal the aggregation behavior of the asphaltenes of varying chemical structures in P3HT, as well the influence of their presence and concentration on the polymer phase structure and blend morphology, paving the way for future development of BHJ solar cells based on the conjugated polymer/asphaltene blends.