writer：3. Hua Yang; Kexin Qu; Haidong Li; He Cheng;* Jidong Zhang*
keywords：solvent vapor anealing, poly(9,9-dioctylfluorene)
source：期刊
specific source：Macromolecular Chemistry and Physics
Issue time：2016年

A new metastable solvent-induced clathrate liquid crystalline phase of β phase (named β’ here) in

crystalline poly(9,9-dioctylfluorene) (PFO) thin film induced by solvent annealing is found by a

combination of in situ ultraviolet and visible spectrophotometry (UV-vis), photoluminescence spectroscopy

(PL), and grazing incidence wide-angle X-ray scattering (GIWAXS). The solvent annealing

process consists of three processes: diffusion of solvent molecules into the film; saturation of solvent

in the film; and drying of the film under nitrogen. The formation of β’ phase with ordered packing of

side chains and disordered packing of backbones occurs during the diffusion process of solvent molecules

into the film. When the solvent molecules penetrate the film, the disordered side chains start to

align themselves to form an ordered structure, and the ordering would gradually in the saturationprocess.

Furthermore, the ordering of side chains drives

an ordered rearrangement of the backbones during the

drying process; however, the crystallinity of the side

chains decreases with the orderly rearrangement of

backbones due to the helical conformation of PFO.