Photoacoustic Effect of Near-Infrared Absorbing Organic Molecules via Click Chemistry

Near-infrared dyes were developed to be contrast agents due to their ability to improve the productivity of photoacoustic (PA) imaging and photothermal therapy (PTT) treatments. During the article, we described in detail the PA and PT effects of a category of organic molecules. F₄-TCNQ could potentially cause a red-shift in the peak PA intensity. The results show that the PTT intensity of the near-infrared dyes with phenyl groups were higher than near-infrared dyes with thiophene groups. We also investigated the photodynamic treatment effect of C1b to demonstrate that these dyes are highly desirable in biochemistry. The high photoacoustic intensity of the organic molecules and the good yield of reactive oxygen species could indicate that these dyes have good potential for a wide range of imaging applications. Finally, we embedded the dye (C1b) in a liposomal hydrophobic phospholipid bilayer (C1b⊂L) to facilitate the application of hydrophobic dyes in biomedical applications, which can be absorbed by cells with good compatible and high stability for the imaging of cellular PA.

Novel benzo[b]thieno[2,3-d]thiophene derivatives with an additional alkyl-thiophene core: synthesis, characterization, and p-type thin film transistor performance

Newly synthesized benzo[b]thieno[2,3-d]thiophene derivatives were employed as active layers of organic field effect transistors, and these transistors showed decent electrical performance.

Preparation and Characterization of Semi-Alicyclic Polyimide Resins and the Derived Alignment Layers for Liquid Crystal Display Technology

Uniform alignment of rigid-rod liquid crystal (LC) molecules under applied voltage is critical for achievement of high-quality display for thin-film transistor-driven liquid crystal display devices (TFT-LCDs). The polymeric components that can induce the alignment of randomly aligned LC molecules are called alignment layers (ALs). In the current work, a series of organo-soluble polyimide (SPI) ALs were designed and prepared from an alicyclic dianhydride, hydrogenated 3,3',4,4'-biphenyltetracarboxylic dianhydride (HBPDA), and various aromatic diamines, including 4,4'-methylenedianiline (MDA) for SPI-1, 4,4'-aminodianiline (NDA) for SPI-2, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane (TMMDA) for SPI-3, and 3,3'-diethyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane (DMDEDA) for SPI-4. The derived SPI resins were all soluble in N-methyl-2-pyrrolidone (NMP). Four SPI alignment agents with the solid content of 6 wt.% were prepared by dissolving the SPI resins in the mixed solvent of NMP and butyl cellulose (BC) (NMP/BC = 80:20, weight ratio). Liquid crystal minicells were successfully fabricated using the developed SPI varnishes as the LC molecule alignment components. The SPI ALs showed good alignment ability for the LC molecules with the pretilt angles in the range of 1.58°-1.97°. The LC minicells exhibited good optoelectronic characteristics with voltage holding ratio (VHR) values higher than 96%. The good alignment ability of the SPI ALs is mainly attributed to the good comprehensive properties of the SPI layers, including high volume resistivity, high degree of imidization at the processing temperature (230 °C), good rubbing resistance, good thermal stability with glass transition temperatures (T_gs) higher than 260 °C, and excellent optical transparency with the transmittance higher than 97% at the wavelength of 550 nm.

Surface wettability controllable polyimides bearing long-chain alkyl groups via phenyl ester linkages by ultraviolet light irradiation

The novel polyimides and copolyimides are synthesized from the diamines having three long-chain alkyl groups connected by phenyl ester linkages, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride or diphenylsulfonetetracarboxylic dianhydride as a tetracarboxylic dianhydride, and 4,4’-diaminodiphenylether as a diamine comonomer. These polyimides show good film-forming ability and good thermal properties. The thin films of obtained polyimides were irradiated by ultraviolet (UV) light ( λmax = 254 nm), and the contact angles for the water decreased from near 100° (hydrophobicity) to near 20° (hydrophilicity) in proportion to irradiated UV light energy. From the result of attenuated total reflectance analysis, it is recognized that the hydrophobic long-chain alkyl groups on the polyimide surface decrease and the hydrophilic groups such as carboxyl groups and hydroxyl groups generate on their surface. Thus, the surface wettability of these polyimides can be controlled by UV light irradiation, and this method is expected to be applied in the field of printed electronics.

Asymmetric-based novel poly(ether-imide)s: Preparation, properties, kinetics of thermal decomposition, and study electrochemical oxidation behavior by using nanocomposite paste of polymer and multi-walled carbon nanotube

A series of novel fluorescent poly(ether-imide)s (PEIs) bearing ether linkage and diarylimidazole pendant in the backbone was successfully prepared by polycondensation reaction between a new unsymmetrical diamine and commercially available tetracarboxylic acid dianhydrides. The PEIs were characterized by Fourier transform infrared, 1H-NMR, UV-vis spectroscopy, fluorimetry, scanning electron microscopy and elemental analysis. The PEIs with inherent viscosities in the range of 0.47–0.63 dL g−1 showed excellent solubility in various aprotic solvents such as N-methylpyrrolidone, dimethyl sulfoxide, N, N-dimethylacetamide and N,N-dimethylformamide. Thermal properties of new PEIs were evaluated by differential scanning calorimetric and thermogravimetric analysis in N2 and air. These polymers showed glass transition temperatures ( Tg) in the range of 269–333 °C and 10% weight loss temperatures above 400 °C in air atmosphere. The data obtained from TGA experiments of these polymers have been applied in different kinetic equations such as Coats–Redfern, Kissinger and Criado methods, to determine the kinetic parameters ( E, ▵ S, ▵ G, ▵ H) and mechanism of thermal decomposition. Herein a method based on the adsorptive stripping cyclic voltammetry technique to investigate electrochemical oxidation of these polymers by using multi-walled carbon nano tubes modified glass electrode is also reported.

Soluble Polyimides Bearing Long-Chain Alkyl Groups on Their Side ChainviaPolymer Reaction

Novel soluble polyimides having long-chain alkyl groups on their side chain were synthesizedviapolymer reaction with the polyimides having phenolic OH groups and 3,4,5-tris(dodecyloxy)benzoic acid (12GA) using N,N′-dicyclohexylcarbodiimide (DCC) as a dehydration reagent. The polyimides having phenolic OH groups were synthesized from the tetracarboxylic dianhydrides such as 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (cyclohexene-DA), 4,4′-hexafluoroisopropylidendi(phthalic anhydride) (6FDA), and 3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA) and aromatic diamines such as 4,4′-diamino-3,3′-dihydroxybiphenyl (HAB). The polymer reactions were carried out in NMP and the progresses of polymer reactions were quantitatively monitored by1H NMR measurements (conversion; 12.2–98.7%). The obtained polyimides bearing long-chain alkyl groups have enough molecular weights, good film-forming ability, good solubility for various organic solvents, and enough thermal stability. The water contact angles of the polyimide films were investigated, and it is noted that the introduction of long-chain alkyl groups increases the hydrophobicity of polyimide surface. These polyimides are expected to be applicable as the functional materials for microelectronics such as the alignment layers of LCDs.

Dendronized polyimides bearing long-chain alkyl groups and their application for vertically aligned nematic liquid crystal displays

Polyimides having dendritic side chains were investigated. The terphenylene diamine monomer having a first-generation monodendron, 3,4,5-tris(n-dodecyloxy)-benzoate and the monomer having a second-generation monodendron, 3,4,5-tris[-3’,4’,5’-tri(n-dodecyloxy)benzyloxy]benzoate were successfully synthesized and the corresponding soluble dendritic polyimides were obtained by polycondensation with conventional tetracarboxylic dianhydride monomers such as benzophenone tertracarboxylic dianhydride (BTDA). The two-step polymerizations in NMP that is a general method for the synthesis of soluble polyimides is difficult; however, the expected dendritic polyimides can be obtained in aromatic polar solvents such as m-cresol and pyridine. The solubility of these dendoronized polyimides is characteristic; soluble in common organic solvents such as dichloromethane, chloroform, toluene and THF. These dendronized polyimides exhibited high glass transition temperatures and good thermal stability in both air and under nitrogen. Their application as alignment layers for LCDs was investigated, and it was found that these polyimides having dendritic side chains were applicable for the vertically aligned nematic liquid crystal displays (VAN-LCDs).