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91.
Electrospinning of polystyrene (PS) and styrene–isoprene–styrene block copolymer (SIS) blends with different composition weight ratios was carried out with a mixed solvent, tetrahydrofuran (THF) and N,N-dimethylformamide (DMF) (80/20, v/v). Electrospun PS/SIS blend fibers were characterized using scanning electron microscopy. The results indicated that the presence of DMF resulted in a beneficial effect on fiber formation and greater electrospinnability of as-spun fibers. Furthermore, the morphological structure and diameters of as-spun fibers from PS and SIS blends were affected by the composition weight ratio and the solution properties. The fibers from 10 wt% solution exhibited the best mechanical properties compared to the fibers from other concentrations for the same composition, and increasing the SIS content one observes a vanishing of PS-related properties, while SIS-related properties emerges. 相似文献
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96.
Maozhang Tian Xi Chen Xinyuan Zou Yuchen Qian Zhang Liu Yaxun Fan 《Molecules (Basel, Switzerland)》2021,26(16)
Surfactant aggregates have long been considered as a tool to improve drug delivery and have been widely used in medical products. The pH-responsive aggregation behavior in anionic gemini surfactant 1,3-bis(N-dodecyl-N-propanesulfonate sodium)-propane (C12C3C12(SO3)2) and its mixture with a cationic monomeric surfactant cetyltrimethylammonium bromide (CTAB) have been investigated. The spherical-to-wormlike micelle transition was successfully realized in C12C3C12(SO3)2 through decreasing the pH, while the rheological properties were perfectly enhanced for the formation of wormlike micelles. Especially at 140 mM and pH 6.7, the mixture showed high viscoelasticity, and the maximum of the zero-shear viscosity reached 1530 Pa·s. Acting as a sulfobetaine zwitterionic gemini surfactant, the electrostatic attraction, the hydrogen bond and the short spacer of C12C3C12(SO3)2 molecules were all responsible for the significant micellar growth. Upon adding CTAB, the similar transition could also be realized at a low pH, and the further transformation to branched micelles occurred by adjusting the total concentration. Although the mixtures did not approach the viscosity maximum appearing in the C12C3C12(SO3)2 solution, CTAB addition is more favorable for viscosity enhancement in the wormlike-micelle region. The weakened charges of the headgroups in a catanionic mixed system minimizes the micellar spontaneous curvature and enhances the intermolecular hydrogen-bonding interaction between C12C3C12(SO3)2, facilitating the formation of a viscous solution, which would greatly induce entanglement and even the fusion of wormlike micelles, thus resulting in branched microstructures and a decline of viscosity. 相似文献
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In this work, the chitosan ternary nanocomposites with two-dimensional (2D) clay platelets and one-dimensional (1D) CNTs have been successfully prepared by a simple solution-intercalation/mixing method in acid media. It was found that the thermal degradation temperature of chitosan (at 50% weight loss) could be only improved in about 20-30 °C by adding 3 wt% either clay or CNTs, however, almost 80 °C increase of degradation temperature could be achieved by adding 2 wt% clay and 1 wt% CNTs together. Dynamic mechanical measurement demonstrated an obviously improved storage modulus for chitosan/clay-CNTs than that for the corresponding binary chitosan/clay or chitosan/CNT nanocomposites with the same total filler content (3 wt%). For the solvent vapor permeation properties, a largely improved benzene vapor barrier property was observed only in chitosan/clay-CNT ternary nanocomposites and depended on the ratio of clay to CNTs. XRD, SEM and TEM results showed that both clay and CNTs could be well dispersed in the ternary nanocomposites with the nanotubes located around the clay platelets. FTIR showed an improved interaction between the fillers and chitosan by using both clay and CNTs. A much enhanced solid-like behavior was observed in the ternary nanocomposites, compared with the corresponding binary nanocomposites with the same total filler content, as indicated by rheological measurement. The unique synergistic effect of two-dimensional (2D) clay platelets and one-dimensional (1D) CNTs on the property enhancement could be tentatively understood as due to a formation of much jammed filler network with 1D CNTs and 2D clay platelets combined together. Our work demonstrates a good example for the preparation of high performance polymer nanocomposites by using nanofillers with different dimensions together. 相似文献
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Xinyuan Qi Ivan L. Garanovich Zhiyong Xu Andrey A. Sukhorukov Wieslaw Krolikowski Arnan Mitchell Guoquan Zhang Dragomir N. Neshev Yuri S. Kivshar 《Photonics and Nanostructures》2010,8(2):62-66
We study both theoretically and experimentally the nonlinear surface waves at the edge of curved waveguide arrays with a surface defect. We show that the nonlinear coupling between different linear modes supported by the array can lead to beam switching to different output waveguides with increasing of the nonlinearity strength. Our experimental observations are in good agreement with the numerical modelling. 相似文献
99.
Yu Peng Yunpeng Yao Lina Li Xitao Liu Xinyuan Zhang Zhenyue Wu Sasa Wang Chengmin Ji Weichuan Zhang Junhua Luo 《化学:亚洲杂志》2019,14(13):2273-2277
Organic–inorganic lead halides have recently emerged as promising alternatives to conventional optoelectronic materials, considering their intriguing physical properties. However, organic–inorganic lead halides featuring chirality are seldom explored. Here, a pair of enantiomorphic organic–inorganic hybrid semiconducting lead halides, (R‐C5H14N2)PbBr4 ( 1R ) and (S‐C5H14N2)PbBr4 ( 2S ), were successfully obtained with the templating of chiral amines. These compounds adopt distinct one‐dimensional infinite quantum helices formed by edge‐shared transformative lead bromide octahedra. Notably, 1R and 2S present mirror circular dichroism (CD) signals due to the chirality transfer of the enantiopure amines. Furthermore, 1R and 2S exhibit phase‐matchable quadratic nonlinear response and typical semiconducting behaviours. This work highlights the potential of lead halides as a new kind of chiral semiconducting materials in spintronic and chiral optical applications. 相似文献
100.
Xihui Gao Sha Li Fei Ding Hongjia Fan Leilei Shi Lijuan Zhu Jing Li Jing Feng Xinyuan Zhu Chuan Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(26):8811-8815
Exosomal microRNAs (miRNAs) are important biomarkers for clinical diagnosis and disease treatment monitoring. However, most approaches for exosomal miRNA detection are time‐consuming, laborious, and expensive. Herein, we report a virus‐mimicking fusogenic vesicle (Vir‐FV) that enables rapid, efficient, and high‐throughput detection of exosomal miRNAs within 2 h. Fusogenic proteins on Vir‐FVs can specifically target the sialic‐acid‐containing receptors on exosomes, inducing efficient fusion of Vir‐FVs and exosomes. Upon vesicle content mixing, the molecular beacons encapsulated in Vir‐FVs specifically hybridize with the target miRNAs in the exosomes, generating fluorescence. Combined with flow cytometry, the Vir‐FVs can not only detect exosomal miRNAs but also distinguish tumor exosomes from normal exosomes by sensing the tumor‐related miRNAs, paving the way towards the rapid and efficient detection of exosomal miRNAs for diagnosis and prognosis prediction of diseases. 相似文献