New aromatic polyimides containing triphenylamine unit were prepared by two different methods, i.e., a conventional two‐step method starting from 4,4′‐diaminotriphenylamine and aromatic tetracarboxylic dianhydrides and the one‐step thioanhydride method starting from the aromatic diamine and aromatic tetracarboxylic dithioanhydrides. Both procedures yielded high‐molecular‐weight polyimides with inherent viscosities of 0.47–1.17 dL/g. Some of these polymers were soluble in organic solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, m‐cresol, and pyridine. All the polyimides afforded transparent, flexible, and tough films, and the color varied from pale yellow to dark red, depending markedly on the tetracarboxylic acid components. The glass transition temperatures (Tgs) of these polyimides were in the range of 287–331°C and the 10% weight loss temperatures were above 520°C in air. The polyimides prepared by the one‐step method exhibited better solubility in organic solvents and had somewhat lower Tgs than the polymers prepared by a conventional two‐step method.

We report the synthesis of a well-defined hyperbranched double hydrophilic block copolymer of poly(ethylene oxide)-hyperbranched-polyglycerol (PEO-hb-PG) to develop an efficient drug delivery system. In specific, we demonstrate the hyperbranched PEO-hb-PG can form a self-assembled micellar structure on conjugation with the hydrophobic anticancer agent doxorubicin, which is linked to the polymer by pH-sensitive hydrazone bonds, resulting in a pH-responsive controlled release of doxorubicin. Dynamic light scattering, atomic force microscopy, and transmission electron microscopy demonstrated successful formation of the spherical core-shell type micelles with an average size of about 200 nm. Moreover, the pH-responsive release of doxorubicin and in vitro cytotoxicity studies revealed the controlled stimuli-responsive drug delivery system desirable for enhanced efficiency. Benefiting from many desirable features of hyperbranched double hydrophilic block copolymers such as enhanced biocompatibility, increased water solubility, and drug loading efficiency as well as improved clearance of the polymer after drug release, we believe that double hydrophilic block copolymer will provide a versatile platform to develop excellent drug delivery systems for effective treatment of cancer.

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Ambipolar organic thin-film transistors (TFTs) based on a fluorinated copper phthalocyanine (F16CuPc)∕copper phthalocyanine (CuPc) homostructure layer were fabricated and characterized. The homostructure TFTs showed typical air-stable ambipolar characteristics, with hole and electron mobilities of 1.44×10−3 and 9.97×10−4cm2∕Vs, respectively, which are comparable to unipolar mobilities in these single-layer devices. X-ray diffraction analysis suggests highly ordered F16CuPc and CuPc polycrystalline thin films could be continuously grown via an intermediate-phase layer in the homostructure.

New aromatic polyamides (aramids) having inherent viscosities of 0.5–2.6 dL/g were prepared by the direct polycondensation of 4,4′‐diaminotriphenylamine with various aromatic dicarboxylic acids in N‐methyl‐2‐pyrrolidone using triphenyl phosphite and pyridine as condensing agents. These aramids were amorphous and soluble in a variety of solvents such as N,N‐dimethyl‐acetamide, dimethyl sulfoxide, and pyridine, and afforded transparent and tough films by solvent casting. The glass transition temperatures of these aramids were in the range of 280–310°C, and the 10% weight loss temperatures were above 430°C in air.