Simulated Glass Transition of Poly(ethylene oxide) Bulk and Film:A Comparative Study
Stepwise coding molecular dynamics (MD) simulations have been carried out on the bulk and film models for poly(ethylene oxide) (PEO) to understand glass transition of amorphous polymer films.Three types of properties —density,energy,and dynamics—are computed and plotted against the temperature for the two systems.It has been confirmed that all these properties can reveal glass transition in both PEO bulk and film systems.All the determined glass transition temperatures (Tss) drop in the same order of magnitude to the experimental data available.Among various methods,the Tgs obtained from the density and energy data are dose to each other if the same space regions are defined,which can suggest the same free volume theory,and dynamic Tgs obtained from mean-squared displacements (MSDs) are highest,which can suggest the kinetic theory for structural relaxation.Consistendy,all these Tgs obtained using different methods show that the Tgs of PEO film are lower than those of PEO bulk.The free surface layers of polymer films dictate this offset.
Chaofu Wu
Department of Chemistry and Materials Sdence, Hunan University of Humanities, Science and Technology, Loudi 417000, the Peoples Republic of China
国际会议
南京
英文
448-456
2012-05-13（万方平台首次上网日期，不代表论文的发表时间）