The solid-liquid interfacial free energy and its anisotropy are crucial quantities in determining the microstructure and mechanical properties of materials. However, most researches mainly concerned the solidliquid co...The solid-liquid interfacial free energy and its anisotropy are crucial quantities in determining the microstructure and mechanical properties of materials. However, most researches mainly concerned the solidliquid coexistence at melting point. In this work, two methods, the critical nucleus method （CNM） and the capillary fluctuation method （CFM）, were combined to get these quantities in undercooled system by molecular dynamics （MD） simulations. The melting point, Tolman length, interfacial free energy and its anisotropy were calculated, and good consistent results from these two methods are obtained. The results of interfacial free energy obtained by CNM and CFM are 103.79 and 102.13 mJ·m^-2, respectively, with the error 〈2%. Meanwhile, both of the methods provide the rank of interfacial free energy by γ7100〉 γ7120 〉 γ 7110 〉 γ112 〉 γ111. The results of the present study are also in good agreement with experimental data and computational data in the literature.展开更多
The effect of surface properties of six types of biomedical materials on their blood compatibility was investigated in this study. The surface roughness of biomaterials was determined by confocal laser scanning micros...The effect of surface properties of six types of biomedical materials on their blood compatibility was investigated in this study. The surface roughness of biomaterials was determined by confocal laser scanning microscopy （CLSM）. The contact angle was observed by contact angle measurement （CAM）. Then the surface free energy （SFE） and interfacial free energy （IFE） were calculated by the contact angle value based on the Owens- Wendt （OW） theoretical model and Young＇ s equation. Meanwhile, hemolytic assay was employed to evaluate the haemolysis. The experimental results showed that the greater roughness was, the greater contact angle would be ; the less proportion of polar component in surface free energy （SFE） was, the lower haemolysis would be.展开更多
Molecular dynamics computer simulation based on the Born-Mayer-Huggins potential function has been carried out to study the effects of cluster size and temperature on the nucleation rate of sodium chloride clusters in...Molecular dynamics computer simulation based on the Born-Mayer-Huggins potential function has been carried out to study the effects of cluster size and temperature on the nucleation rate of sodium chloride clusters in the temperature range of 580 K to 630 K. Clusters with 256 and 500 NaCl molecules have been studied and the results have been compared with those obtained from 108 molecule clusters. The melting point (MP) of the clusters were observed to increase with the size of the clusters and can be well described by a linear equation MP=1107(37)-1229(23)N -1/3 (N is the number of molecules in the cluster). The nucleation rate was found to decrease with increasing the cluster size or temperature. Various nucleation theories have been used to interpret the nucleation rates obtained from this molecular dynamics simulation. It is possible to use a constant diffuse interface thickness to interpret the nucleation rate from the diffuse interface theory in the temperature range of this study. However,the interfacial free energy estimated from classical nucleation theory and diffuse interface theory increases too fast with increasing the temperature while that from Gran-Gunton theory does not change with changing temperatures. The sizes of critical nuclei estimated from all the theories are smaller than those estimated from our simulations.展开更多
文摘The solid-liquid interfacial free energy and its anisotropy are crucial quantities in determining the microstructure and mechanical properties of materials. However, most researches mainly concerned the solidliquid coexistence at melting point. In this work, two methods, the critical nucleus method （CNM） and the capillary fluctuation method （CFM）, were combined to get these quantities in undercooled system by molecular dynamics （MD） simulations. The melting point, Tolman length, interfacial free energy and its anisotropy were calculated, and good consistent results from these two methods are obtained. The results of interfacial free energy obtained by CNM and CFM are 103.79 and 102.13 mJ·m^-2, respectively, with the error 〈2%. Meanwhile, both of the methods provide the rank of interfacial free energy by γ7100〉 γ7120 〉 γ 7110 〉 γ112 〉 γ111. The results of the present study are also in good agreement with experimental data and computational data in the literature.
文摘The effect of surface properties of six types of biomedical materials on their blood compatibility was investigated in this study. The surface roughness of biomaterials was determined by confocal laser scanning microscopy （CLSM）. The contact angle was observed by contact angle measurement （CAM）. Then the surface free energy （SFE） and interfacial free energy （IFE） were calculated by the contact angle value based on the Owens- Wendt （OW） theoretical model and Young＇ s equation. Meanwhile, hemolytic assay was employed to evaluate the haemolysis. The experimental results showed that the greater roughness was, the greater contact angle would be ; the less proportion of polar component in surface free energy （SFE） was, the lower haemolysis would be.
文摘Molecular dynamics computer simulation based on the Born-Mayer-Huggins potential function has been carried out to study the effects of cluster size and temperature on the nucleation rate of sodium chloride clusters in the temperature range of 580 K to 630 K. Clusters with 256 and 500 NaCl molecules have been studied and the results have been compared with those obtained from 108 molecule clusters. The melting point (MP) of the clusters were observed to increase with the size of the clusters and can be well described by a linear equation MP=1107(37)-1229(23)N -1/3 (N is the number of molecules in the cluster). The nucleation rate was found to decrease with increasing the cluster size or temperature. Various nucleation theories have been used to interpret the nucleation rates obtained from this molecular dynamics simulation. It is possible to use a constant diffuse interface thickness to interpret the nucleation rate from the diffuse interface theory in the temperature range of this study. However,the interfacial free energy estimated from classical nucleation theory and diffuse interface theory increases too fast with increasing the temperature while that from Gran-Gunton theory does not change with changing temperatures. The sizes of critical nuclei estimated from all the theories are smaller than those estimated from our simulations.
