Molecular interactions are the key to understanding the structure and properties of materials. Also, it is critical of chiral recognition. Since the molecular interactions at play in chiral discrimination is difficult...Molecular interactions are the key to understanding the structure and properties of materials. Also, it is critical of chiral recognition. Since the molecular interactions at play in chiral discrimination is difficult to investigate under traditional experiment conditions. We have undertaken a computer experiment of van der Waals interaction between chiral molecules and a polymer, which works for chiral separation. Building molecular models, choosing proper force field and Monte Carlo method, we have calculated the difference of interaction energy between isotactic poly (triphenylmethyl methacrylate) and (+) hexahelicene or (-) hexahelicene. It is finally found about 1.379 4 kJ/mol between the polymer and the two chiral hexahelicenes. Reasonably, this difference is regardd as the main reason which induced chiral separation. Furthermore, we compared the results from computer smulation with that from experiment. It can be seen that some details during chiral separation process, such as trailing effect, can also be predicted, and be consistent with the experiment results. Finally, the effective structureal characteristics of the recognition site are pointed out.展开更多
In this paper, we discussed the drying behavior of monodispersed polystyrene latex at high temperature with particular attention to the morphological evolution during film formation process. At the beginning of the wa...In this paper, we discussed the drying behavior of monodispersed polystyrene latex at high temperature with particular attention to the morphological evolution during film formation process. At the beginning of the water evaporation, a skin film with some defects was formed at latex/air interface, water evaporated thereby in a constant rate. During this stage, a drying front advanced from the top film towards the bulk dispersion. Afterwards, most water was lost, and water evaporation rate was less than that of the initial stage. In this case, the whole system became immobile, and another drying front developed from the interior region outside the system. Two distinct boundaries between completely dried region and wet region corresponding to the opposite directions of the second drying front were found if the film peeled from the container bottom surface. Besides, some particular morphologies were found in the completely dried region, which was likely related to preferable coalescence among the particles induced by capillary force due to water evaporation.展开更多
文摘Molecular interactions are the key to understanding the structure and properties of materials. Also, it is critical of chiral recognition. Since the molecular interactions at play in chiral discrimination is difficult to investigate under traditional experiment conditions. We have undertaken a computer experiment of van der Waals interaction between chiral molecules and a polymer, which works for chiral separation. Building molecular models, choosing proper force field and Monte Carlo method, we have calculated the difference of interaction energy between isotactic poly (triphenylmethyl methacrylate) and (+) hexahelicene or (-) hexahelicene. It is finally found about 1.379 4 kJ/mol between the polymer and the two chiral hexahelicenes. Reasonably, this difference is regardd as the main reason which induced chiral separation. Furthermore, we compared the results from computer smulation with that from experiment. It can be seen that some details during chiral separation process, such as trailing effect, can also be predicted, and be consistent with the experiment results. Finally, the effective structureal characteristics of the recognition site are pointed out.
文摘In this paper, we discussed the drying behavior of monodispersed polystyrene latex at high temperature with particular attention to the morphological evolution during film formation process. At the beginning of the water evaporation, a skin film with some defects was formed at latex/air interface, water evaporated thereby in a constant rate. During this stage, a drying front advanced from the top film towards the bulk dispersion. Afterwards, most water was lost, and water evaporation rate was less than that of the initial stage. In this case, the whole system became immobile, and another drying front developed from the interior region outside the system. Two distinct boundaries between completely dried region and wet region corresponding to the opposite directions of the second drying front were found if the film peeled from the container bottom surface. Besides, some particular morphologies were found in the completely dried region, which was likely related to preferable coalescence among the particles induced by capillary force due to water evaporation.
