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A novel diamine named (2,2′-bibenzoxazole)-5,5′-diamine (DBOA) and derived polyimides (PIs) were successfully synthesized. The rigid, linear, symmetrical molecular structure and the strong charge transfer complex (CTC) were considered to be the reasons for the improved molecular packing and enhanced thermal properties of the polymers. These DBOA based PIs exhibited a higher glass transition temperature (Tg) and lower coefficient of thermal expansion (CTE) than traditional benzoxazole (BOA) based PIs. Meanwhile, the PI derived from DBOA and BPDA (3,3′,4,4′-biphenyltetracarboxylic dianhydride) exhibited high Tg (395 °C) and low CTE (8.9 ppm per °C), and is expected to be applied in organic light-emitting diode (OLED) displays.

Chopped polyimide (PI) fiber-reinforced polyether ether ketone (PEEK) composites with different fiber content (0%, 10%, 20%, and 30%) were prepared via melt extrusion using a twin-screw extruder. The impact strength of these composites significantly improved from 4.9 kJ m−2 to 9.3 kJ m−2 with the increase of the PI fiber content from 0% to 30%. Tensile strength, tensile modulus, and flexural strength also increased with the increase in PI fiber content. In addition, the heat deflection temperature increased significantly from 160°C to 318°C. The results of the dynamic mechanical analysis revealed that the storage modulus increased considerably. The relationship between mold temperature and composite properties was investigated, and using differential scanning calorimetry, it was shown that the increase in mold temperature improved the degree of polymer crystallization and the bonding capability of the fiber and resin interface. As a result, the mechanical properties of the composite material were improved.

Zwitterionic nano-silica (SiO2 NPs) obtained by lysine surface modification was used as a hydrophilic inorganic filler for preparing a poly(aryl ether nitrile) (PEN) nanocomposite membrane via an immersion precipitation phase inversion method. The effects of zwitterionic SiO2 NPs addition on the morphology, separation and antifouling performance of the synthesized membranes were investigated. Zwitterionic surface modification effectively avoided the agglomeration of SiO2 NPs. The PEN/zwitterionic SiO2 NPs composite membranes exhibited improved porosity, equilibrium water content, hydrophilicity and permeability due to the introduction of hydrophilic SiO2 NPs in the casting solution, and the optimal pure water flux was up to 507.2 L m−2 h−1, while the BSA rejection ratio was maintained at 97.4%. A static adsorption capacity of 72.9 μg cm−2 and the FRR up to 85.3% in the dynamic antifouling experiment proved that the introduction of zwitterionic SiO2 NPs inhibited irreversible fouling and enhanced the antifouling ability of the PEN membrane.

Porous polyamide films were prepared by a simple electrostatic spray deposition method for the first time. The polymer solution quickly was dispersed into micron-sized droplets and deposited on the substrate under the electrostatic field forces. With the continue depositing of the droplets and evaporating of the solvent, many voids formed between the droplets to form a porous structure. Thanks to existence of these porous channels, the ion transmission could be effectively increased. Therefore, compared with the film prepared by traditional blade coating, the porous film exhibited a smaller redox potential interval and shorter response time. Introducing of silver nanowires (AgNWs) into the polymer solution wouldn't impede the formation of porous structure, and electrochromic response time for the obtained polyamide/AgNWs film can be effectively improved. The bleaching/coloring time could reach 0.8 s/1.2 s, which is the best record for the polyamide based electrochromic film. These results showed that, electrostatic spraying technology is a promising and efficiently method to prepare polymer film with good electrochromic property.

Resumen del póster presentado a la "5th International Conference on Hybrid and Organic Photovoltaics" celebrada en Sevilla (España) del 5 al 8 de mayo de 2013., The conversion of solar energy in electricity is likely to play a key role as one of the technologies that can replace fossil fuels as a source of energy supply. Cheaper solar energy technologies are therefore under intensive study, and in this context dye sensitized solar cells (DSSCs) have emerged as an important class of photovoltaic devices. The dye molecular structure plays a very important role in the operation of a DSSC. Several molecular structures have been tested as sensitizers for these cells, among which stand out the donor-π-acceptor (D- π –A) systems. Such molecules have a donating group of electronic density, attached to an attractor moiety through a π-conjugated spacer. This particular arrangement allows a strong intramolecular charge transfer, thereby facilitating the electron transfer between the dye and the TiO2 electrode. In the literature, the vast majority of donors for this application include a unit of diphenyl, dialkyl or triaryl amines. In this communication we have chosen a proaromatic ring of 4Hpyranylidene and as the electron acceptor /anchoring group we have used a 2-cyanoacrylic acid moiety. Most of the organic sensitizers described in the bibliography, have a thiophene ring (or a derivative thereof) in the spacer because it provides good stability and good photovoltaic properties. To examine how the electronic character of the spacer affects the photovoltaic process, the synthesis of new molecules which incorporate into the spacer different heterocycles has been carried out. The selected bridges have been: 1-methyl-1H-pyrrole, furan, thiophene and thiazole. We have studied the thermal stability as well as the electrochemical and the optical properties of all dyes synthesized. Furthermore, measures of photovoltaic response have been carried out obtaining efficiency values between 1.44% and 5.50%.