Sandwich layer structure of a novel polyimide with methylene spacing groups in biphenyl side chain

The aggregation structure of a novel polyimide (PI-6) with six methylene flexible spacing groups in biphenyl side chain was investigated using polarized optical microscope (POM), wide/small-angle X-ray diffraction (WAXD/SAXD) and molecular simulation approach. Depending on increasing temperature, the sandwich layer aggregation structure of PI-6 was developed from the thermo reversible gel. The backbones are lamellar stacking with 11.5 Å thickness. The side chains are randomly packed into the backbone lamellar intervals and the width of this layer for both backbone and side chain is about 23.1 Å which is consistent with the simulation data.