A series of pyrene derivatives with different asymmetrical substituents were successfully synthesized and characterized.The geometrical electronic structures of the asymmetrical pyrene derivatives were performed by density functional theory(DFT) calculations.The results of photophysical spectra and electrochemical analysis indicated that the optical or electric properties of the pyrene derivatives could be tuned by adjust the π-conjugation lengths of the substituents.Furthermore,through a phase exchange self-assembly method,the highly organized morphologies were observed by SEM.
Peng-Xia LiangDong WangZong-Cheng MiaoZhao-Kui JinHuai YangZhou Yang
A novel type of aromatic poly(ether ether ketone)s with carboxyl groups were prepared by polycondensation of 4,4-bis(4-hydroxyphenyl)pentanoic acid with difluoro-monomers.Their molecular structures were determined by 1H-NMR and IR,respectively.Their molecular weights were measured by gel permeation chromatography(GPC),which showed that all the polymers had high molecule weights(>42 000).Due to the long side chains of polymers,all the polymers had good solubility(soluble in NMP,DMAc,THF,etc.).The differential scanning calorimeter(DSC) detected their excellent glass transition temperatures(Tg) up to 195 ℃.The Tg increased with the content of carboxylic units in the polymer chains,because the interactions of H bonds increased with increasing content of carboxylic.The polymers could form transparent and flexible films,which make them a candidate for membrane materials.
A series of high birefringence liquid crystalline molecules with cyano, isothiocyanato and trifluoromethyl terminal compounds based on naphthylethyne core was successfully synthesized and characterized. The molecular structures of the intermediates and resulting compounds were confirmed by Fourier transform infrared(FT-IR), nuclear magnetic resonance(NMR), mass spectrometry(MS), and elemental analysis(EA). Their thermal stability, transition temperatures, and phase sequences were investigated by simultaneous thermal analyzer polarized(STA), optical microscopy(POM) and differential scanning calorimetry(DSC). The birefringence was measured by using an Abbe refractometer. In addition, the selective reflection characteristics with naphthylethyne compounds were also studied.
Yu-Zhen ZhaoDong WangZe-Min HeGang ChenLan-Ying ZhangHai-Quan ZhangHuai Yang
Two types of micro /nano structures,microsphere and nanofibre,were prepared by electro spinning technique and spray drying technique,with the soluble fluorinated poly ( ether ether ketone) ( 3 F-PEEK) as the matrix. The micro / nano structures were exhibited in the scanning electron microscope ( SEM) micrograghs,and the separated nanofibre and microsphere were observed. The sizes of micro/nano structures were measured by the statistical analysis method. We designed experiments to connect up all the micro / nano structures to form new three dimensional micro / nano structures that were observed by SEM. In the experiments,supercritical carbon dioxide ( CO2 ) was selected as the welding solvent. A series of nanofibers were welded to form three dimensional netlike structures,and the particles were welded to form a porous film. The welding processes were studied by varying the exposure temperature,and the welding mechanism was discussed.
