Syndiotactic Polystyrene Nanofibers Obtained from High-Temperature Solution Electrospinning Process

Electrospun syndiotactic polystyrene (sPS) fibers with a diameter of 150−400 nm were successfully prepared via high-temperature electrospinning of solutions with different concentrations in an o -dichlorobenzene solvent. From the polarized FTIR spectra, the sPS chains in the as-spun fibers were amorphous and exhibited a preferential chain orientation along the fiber axis. Upon thermal annealing at a temperature lower than 270 °C, sPS crystals with the α-form modification were developed, as revealed by the electron diffraction patterns of the individual fiber segments. The orientation factor of the (002) plane was determined to be 0.94−0.97, relatively independent of the annealing temperature. Solvent-induced crystallization readily took place in these submicrometer-sized fibers, giving rise to the δ-form sPS crystals, as revealed by the FTIR spectra and WAXD patterns. The absorbed solvents could subsequently be expelled by boiling in ethanol, leaving the cavities available for the next solvent treatment. In contrast with the bulk films, sPS fiber mats exhibit a promising application in chemical separation and water purification due to their large surface area as well as high solvent permeation resulting from its small-fiber diameter character.