Blue fluorescent polyamides containing naphthalene and oxadiazole rings

Abstract

New polyamides containing 1,3,4-oxadiazole and naphthalene rings were prepared by low-temperature solution polycondensation reaction of a new diamine containing preformed oxadiazole ring with various aromatic diacid chlorides. Elemental analysis, mass, infrared, and nuclear magnetic resonance spectroscopy were used to confirm the structure of the monomers and corresponding polymers. The thermal stability and glass transition temperatures of these poly(oxadiazoleamide)s were measured and compared with those of related polymers. Their good solubility allows them to be processed in very thin films with smooth surfaces, without pinholes or cracks, when studied by atomic force microscopy. Upon irradiation with UV light the polymers showed photoluminescence maxima in the blue spectral range, both in solution and in solid state. Cyclic voltammetry (CV) was performed in order to obtain information about the electrochemical stability and reversibility of the redox processes of these polyamides. The highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels, and electrochemical and optical band gap values were calculated by using the results of CV and UV/vis, respectively, showing very good electron and hole injection and transport characteristics. These properties make the present polymers suitable for application in electroluminescent devices. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: [893][894][895][896][897][898][899][900][901][902][903][904][905][906] 2011 Fully aromatic poly(1,3,4-oxadiazole)s form another class of high performance polymers that are designated for use in small quantities, but with very high end-value. 22 High performances include high thermal resistance in oxidative atmosphere, good hydrolytic stability, tough mechanical properties, optical properties, highly ordered systems, and other special properties determined by the electronic structure of this particular heterocycle. [23][24][25][26] There is currently much interest in high-brightness blue light-emitting diodes to be used in full colour displays, full colour indicators, and light sources for lamps, which have high efficiency and high reliability as characteristics. For such a purpose polyoxadiazoles are very attractive because, due to the electron-withdrawing character of the 1,3,4-oxadiazole rings, they can

Insights into the Chain and Local Mobility of Some Aromatic Polyamides and Their Influence on the Physicochemical Properties

“…Both polymeric powders showed characteristic amide group absorptions in the range of 3434–3428 cm −1 (NH stretching, wide bands), 1681–1668 cm −1 (carbonyl stretching, amide I), and 1529 cm −1 (NH deformation, amide II). An in‐depth study regarding the structural identification of the monomers and polymers was already published …”

Multicenter Polyester Initiators for the Preparation of Graft Copolymers with Oligo(2‐Oxazoline) Side Chains

“…2‐[4‐(2‐Br‐ethyl)]phenylsulfonyl hydroquinone ( 1 ), 4,4′‐alkanedioyldioxydibenzoic acids ( 2a–2g ), and 4,4′‐alkanedioyldioxydibenzoyldichlorides ( 3a–3g ), 4,4‐oxydibenzoyldicloride and 2,5‐biphenyldicarbonyldichloride, 2‐isopropyl‐2‐oxazoline were obtained according to the known procedures. 2‐Ethyl‐2‐oxazoline, diphenyl oxide, 1‐chloronaphalene and 1,1,2,2‐tetrachloroethane (Aldrich) were dried over calcium hydride and distilled.…”

Six-member polyimides incorporating redox chromophores

“…However, because of its low melting temperature, the vacuum-deposited film of PBD showed a strong tendency to crystallize at the elevated temperature reached during device operation. Accordingly, many materials, including organic small molecules and polymers with oxadiazole units in the backbone or in side chains, have been designed and prepared as HB/ET materials with high or without melting temperature [13][14][15][16][17]. The use of electroluminescent thin films made from highly thermostable polymers would avoid the thermal degradation in the final device while in service at elevated temperatures.…”