Molecular modeling of the intermediate smectic mesophase in polyethylene terephthalate

An atomistic molecular model has been developed to study the development and existence of the intermediate smectic mesophase and crystalline phases of the oriented polyethylene terephthalate (PET) molecules. A meridional mesophase reflection were observed as a result of a smectic arrangement of the polymer chains prior to crystallization, which requires the presence of register planes, perpendicular to the chain direction. The existence of PET chains in the fully extended stiff conformation was found to be responsible for the liquid crystalline transient mesophase reflection. PET chains in a strained conformation did not exhibited the meridional mesophase reflection due to equal electron density along the PET chain.