Microporous polyimides with high surface area and CO selectivity fabricated from cross-linkable linear polyimides.

Linear polyimides of intrinsic microporosity have been intensively investigated for gas separation due to their microporous structure and high surface area. The microporous structure in the linear polyimides of intrinsic microporosity comes from their contorted structure. Therefore, most linear polyimides without contorted structure do not have micropores.

Effect of External Electric Field on the Ordered Structure of Molecular Chains and Hole Mobility in Regioregular Poly(3-hexylthiophene) with Different Molecular Weights.

This research investigated the effect of a high-voltage external electric field on the ordered structure of molecular chains and hole mobility in regioregular poly(3-hexylthiophene) (P3HT) with different molecular weights through X-ray diffraction, atomic force microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, micro-Raman spectroscopy, UV-vis spectroscopy, photoluminescence spectroscopy, and organic field-effect transistors. The optimal magnitude of the external electric field was 5000 V/cm. With the optimized electric field applied to a series of P3HT films, the carrier mobility of all P3HT films increased, and the increase rate changed from 105% to 56%, closely depending on the increase in molecular weight from 33 kg/mol to 100 kg/mol.

Dynamic Evolution from Chain Disorder to Order of PTB7 Condensed State Structures under External Fields.

In this research, the effect of external fields (solvent, temperature, solution concentration, and external force) on dynamic evolution from chain disorder to order of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2- b:4,5- b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4- b]thiophenediyl]] (PTB7) condensed state structures was explored by UV-vis absorption spectra, atomic force microscope, and transmission electron microscopy (TEM). It was found that PTB7 main chains presented amorphous conformations induced by the poor solvent 1,2-dichloroethane. However, the local ordered aggregation appeared in amorphous conformations when the solubility of the poor solvent was again lowered by reducing temperature.