Computer simulation studies of the influence of side alkyl chain on glass transition behavior of carbazole trimer  

作　　者：Chunyang Yu Li Ma Wei Huang Yongfeng Zhou Jingui Qin Deyue Yan 

机构地区：[1]State Key Laboratory of Metal Matrix Composites,School of Chemistry & Chemical Engineering,Shanghai Jiao Tong University [2]Department of Chemistry,Wuhan University

出　　处：《Science China Chemistry》2017年第3期377-384,共8页中国科学（化学英文版）

基　　金：supported by Center for High Performance Computing,Shanghai Jiao Tong University;the National Basic Research Program(2012CB821500,2013CB834506);the China National Funds for Distinguished Young Scholar(21225420);the National Natural Science Foundation of China(21404070,21474062,91127047);the "Shu Guang" project supported by Shanghai Municipal Education Commission;Shanghai Education Development Foundation(13SG14)

摘　　要：In this work,all-atom molecular dynamics simulations were employed to study the influence of the side alkyl chain on glass transition behavior of several carbazole trimers(CT) in a temperature range from 423 to 183 K.The glass transition temperatures were obtained from the break in the slope of the volume-temperature curves and found to agree with the experimental values.The short time dynamics of four CT molecules were probed by usingvelocity autocorrelation functions and mean-square displacements.The current studies showed that the dynamics of CT systems can be easily interpreted through the cage effect.Furthermore,the investigation of the torsional autocorrelation function and P_(2-state)/P_(3-state) functions showed that the rotational barriers of side chains can slow down the conformational relaxation and lead to stronger temperature dependence of conformational relaxation.The relaxation time,characteristic time of P_(2-state)(t) and P_(3-state)(t) functions were all found to have Arrhenius-type temperature dependence.In this work,all-atom molecular dynamics simulations were employed to study the influence of the side alkyl chain on glass transition behavior of several carbazole trimers（CT） in a temperature range from 423 to 183 K.The glass transition temperatures were obtained from the break in the slope of the volume-temperature curves and found to agree with the experimental values.The short time dynamics of four CT molecules were probed by usingvelocity autocorrelation functions and mean-square displacements.The current studies showed that the dynamics of CT systems can be easily interpreted through the cage effect.Furthermore,the investigation of the torsional autocorrelation function and P2-state/P3-state functions showed that the rotational barriers of side chains can slow down the conformational relaxation and lead to stronger temperature dependence of conformational relaxation.The relaxation time,characteristic time of P2-state（t） and P3-state（t） functions were all found to have Arrhenius-type temperature dependence.

关 键 词：carbazole trimer molecular dynamics simulation glass transition relaxation time 

分 类 号：O633.5[理学—高分子化学]