The spirobichroman-based polyimides with different side groups: from structure-property relationships to chain packing and gas transport performance.

Spirobichroman-based polymers with high gas permeability and selectivity are promising for their applications as membranes in gas separation. In this study, three spirobichroman-based polyimides (PIs; 6FDA-FH, 6FDA-DH, and 6FDA-MH) were synthesised by the polyreaction between diamines containing different substituents (benzene ring, pyridine ring, and methyl group) and 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA). The physical properties, gas transport behaviour, -spacing, dihedral angle of molecules, and fractional free volume of the PIs were investigated through experiments and molecular simulations.

Dual-Switching Electrochromism and Electrofluorochromism Derived from Diphenylamine-Based Polyamides with Spirobifluorene/Pyrene as Bridged Fluorescence Units.

Electrochromic (EC)/electrofluorochromic (EFC) bifunctional materials are receiving great attention because of their promising applications in optoelectronic devices. However, the development of ideal EC/EFC bifunctional materials is still a great challenge because of the poor integration of EC/EFC performances (optical contrast, response speed, and switching stability). Herein, we reported two novel diphenylamine-based mixed valence (MV) polyamides (S-HPA and P-HPA) with spirobifluorene (2,7-positions) and pyrene (1,6-positions) as bridged fluorescence units, respectively, showing impressive cyclability and fluorescence contrast with rapid switching.

Soluble Polyimides Bearing ()-Hydrogenated Bisphenol A and ()-Hydrogenated Bisphenol A Moieties: Synthesis, Properties and the Conformational Effect.

In this work, hydrogenated bisphenol A (HBPA) based dinitro mixed isomers (1a' and 1a) were synthesized and separated via vacuum distillation under the monitor of DSC and H NMR. Corresponding diamines (2a' and 2a) were separately polycondensed with five commercial dianhydrides via a two-step thermal imidization to obtain PI-(1'-5') and PI-(1-5). All the polyimides could afford flexible, tough, and transparent films, and most of them were readily soluble not only in common polar solvents like DMAc, but also in low boiling point solvents such as chloroform.