Theoretical Simulation Of Self-assembly Behaviors Of The TP-based Side-chain Discotic Liquid Crystalline Polymers And Polymers Modified Nanoparticles

Polymer self-assembly is a discipline that studies the weak interaction between polymers,between polymers and small molecules,and between polymers and nanoparticles or colloidal particles,such as hydrophobic interactions,hydrogen bonds and coordination bonds,electrostatic interactions forces,dipole interactions,?-?interactions,etc.,and through non-covalent bonds self-assembly into rich and diverse supramolecular ordered structures.Through the experimental design of the physical and chemical properties such as the shape,size,surface properties,and interaction methods of the basic particles during the self-assembly process,the interaction between particles can be regulated,thereby driving the self-assembly behavior of the designed supramolecular ordered structure.It is expected to obtain materials with special properties in this way.The design idea is widely used in the preparation of new characteristic materials such as optical,electrical,magnetic and even biomedical,which brings opportunities and challenges to the development of new generation materials.Computer simulation has important guiding significance for the study of molecular self-assembly because of its superiority in time and space,the realizability of modeling and the controllable reaction process of the system.This paper mainly investigate the effect of grafting density on the self-assembly behavior of Triphenylene?TP?-based discotic liquid crystal polymers?SDLCPs?from the perspective of theoretical simulation,and unfolds the self-assembly behaviors of multiple nanoparticles with surface grafted polymers in solution.Triphenylene derivatives are a type of discotic liquid crystals,which can self-assemble into different liquid crystal phases under the action of peripheral alkyl chains.In this paper,based on the previous experimental and theoretical research on SDLCPs,we constructed a coarse-grained model(A_kB_lC₄D_5×m)_n,and performed dissipative particle dynamics?DPD?methods to investigate the role of graft density how to influence self-assembly behavior of SDLCPs.We explored the coupling effect between the main chain and the side-chain TP discogens with various length alkyl tails,and how the rigidity of the main chain,grafting density and spacer lengths affect the self-assembled morphologies of SDLCPs.Nine phases have been obtained with the former standing for the assembly of discogens,and the latter standing for the aggregation of the main chain:random sphere-bulk(Sph_ran-Bulk),random column-network(Col_ran-Net),random column-cluster(Col_ran-Clu),nematic column-column(Col_ne-Col),hexagonal column-column?Col_h-Col?,hexagonal column-amprphous(Col_ne-Am),nematic column-cluster(Col_ne-Clu),random sphere-cluster(Sph_ran-Clu),random sphere-column(Sph_ran-Col).It is deduced that a moderate grafting density,a polymer backbone with sufficient length and alkyl tails with medium length ensure SDLCPs form ordered columnar mesophases.And the research indicates that the volume fraction effect is an important reason for the different structures of self-assembly.The double columnar phases(Col_ne-Col and Col_h-Col)appearance in high grafting density and sufficiently long backbones,which is consistent with experimental studies.All these results provide an effective basis and helpful guidance for the in-depth research of such kinds of fascinating organic semiconducting materials,from the view of grafting density.Self-assembly of colloidal particles with surface anisotropy is one of the important methods for preparing new materials.By adjusting the nature and action mode of the anisotropic sites on the particle surface,from the molecular design point of view to explore the appropriate synthetic route,researchers have developed many simple and efficient synthesis techniques;the orientation controllable self-assembly of anisotropic particles has made tremendous progress in the fields of biomedicine,materials science,electronic information and so on.Here,we have research the the self-assembly behavior of multiple nanoparticles with surface grafted polymers in solution by using DPD method.After in-depth exploration of factors such as graft density,graft chain length,number and diameter of nanoparticles,a total of six different stacking structures were obtained.Among them,We found that when the morphology of nanoparticles is regularly stacked,it is similar to the atomic hybrid orbital.The morphologies divided into two types:aggregated packed and dispersedly packed,presents dimers,regular triangles,regular tetrahedrons,triangular bipyramids,and regular octahedrons,etc..We explored the controllability of its assembly morphology,and explained the effects of various factors on self-assembly behavior from the perspectives of the volume effect of polymer chains and nanoparticles and the change in the distance between nanoparticles.This research will provide theoretical support and guidance for the self-assembly simulation of multiple nanoparticle grafted polymers and the diversity of their topologies.