There is no crystalline diffraction of wide-Angle X-ray to be discovered in PES

but there is birefringence effect both in its bulk and solution. Its morphological structure unit is a rodlike macromolecule which drrdnges regularly to form domdins

then these domains pack further to form a rodlike submicroscopic structure. The different chain rigidities are due to the different chain structures which induce different dimensions of morphological structure and packing patterns. These morphological structures change with external conditions.All of the above characteristic structures form an important basis for the study of the meso-phase of PES.