Novel organosoluble aromatic polyimides bearing pendant methoxy‐substituted triphenylamine moieties: Synthesis, electrochromic, and gas separation properties

Abstract

Four series of polyimides I–VI with pendent triphenylamine (TPA) units having inherent viscosities of 0.44–0.88 dL/g were prepared from four diamines with two commercially available tetracarboxylic dianhydrides via a conventional two‐step procedure that included a ring‐opening polyaddition to give polyamic acids, followed by chemical cyclodehydration. These polymers were amorphous and could afford flexible films. All the polyimides had useful levels of thermal stability associated with high softening temperatures (279–300 °C), 10% weight‐loss temperatures in excess of 505 °C, and char yields at 800 °C in nitrogen higher than 58%. The hole‐transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyimide films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited a or two reversible oxidation couples at 0.65–0.78 and 1.00–1.08 V versus Ag/AgCl in acetonitrile solution. The polymer films revealed electrochromic characteristics with a color change from neutral pale yellowish to blue doped form at applied potentials ranging from 0.00 to 1.20 V. The CO2 permeability coefficients (P) and permeability selectivity (P/P) for these polyimide membranes were in the range of 4.73–16.82 barrer and 9.49–51.13, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7937–7949, 2008

Synthesis and properties of high‐performance functional polyimides containing rigid nonplanar conjugated tetraphenylethylene moieties

“…S6) and shows very low transparency in the visible region with λ 0 of 513 nm 49. Other reported functional PI containing triphenylamine (TPA) moieties also appeared as dark red brown to deep brown, with λ 0 higher than 500 nm 50, 51. The improvement in color and transparency of the TetraPEDA‐based PI may be due to the large aromatic rigid nonplanar conjugated structure directly connected with the imide unit, which may induce a high steric hindrance and low inductive effect and thus effectively suppress the formation of intermolecular CTC of polymer chains.…”

Synthesis and identification of organosoluble polyimides: thermal, photophysical and chemiluminescence properties

“…[6][7][8] Significant synthetic efforts in the area of high-performance polymers have been focused on improving the processability and solubility of PIs through the design and synthesis of new monomers. Various structural modifications can be made to the PI backbone to modify the polymer properties, such as insertion of flexible linkages on the main chain, 9-13 use of noncoplanar 14 or asymmetric monomers [15][16][17][18][19] and incorporation of pendant groups in the polymer backbone, [20][21][22][23][24][25][26][27][28][29] with results including lower interchain interactions or a reduced polymer chain stiffness. Depending on the type and amount of structural modifications, melting temperatures can be lowered and solubility improved, resulting in processable materials.…”

Highly soluble fluorinated polyimides based on an asymmetric bis(ether amine): 1,7‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene

“…Aromatic polyimides are well known as high‐performance polymeric materials because of their good chemical resistance, high mechanical strength, and excellent thermal stability 1–3. Incorporation of specific functionality into the polyimide backbones leads to various advanced functional materials that exhibit certain advantageous properties, such as electrochromic, gas separation, charge‐transporting, nonlinear optical, highly refractive, and photosensitive properties 4–9. Despite their outstanding properties, most of aromatic polyimides have high melting or glass‐transition temperatures ( T g ) and are insoluble in most organic solvents because of their rigid backbones and strong interchain interactions.…”