Luminescent core–shell nanoparticles (NPs) with crosslinked aggregation-induced emission (AIE) core structures, which exhibited excellent emission independent of the dispersion state of the NPs, have been developed by a facile one-pot method based on the self-assembly of an amphiphilic block copolymer poly(PEGMA)-b-poly(DB3VT). Core–shell micelles with a poly(DB3VT) core were formed from poly(PEGMA)-b-poly(DB3VT) in tetrahydrofuran (THF)/H2O condition, and the crosslinked AIE-based structure was selectively incorporated into the core by the Suzuki coupling reaction between poly(DB3VT) blocks and tetraphenylethylene (TPE)-based coupling monomers at the same time. This method afforded a uniform NP with a crosslinked TPE-based AIE core structure. The obtained NP exhibited excellent emission both in diluted solution and solid states. This result indicated that the formed TPE-based AIE core structure was always aggregated regardless of NP dispersion owing to the crosslinking as we expected. The crosslinked TPE-based AIE core structure, which was related to the emission property, was readily tuned by the selection and combination of coupling monomers in the Suzuki coupling reaction. By incorporating electron-deficient units into the core, the emission color could be successfully tuned from yellow-green to orange and red while maintaining the emission property independent of the state of the NP dispersion. These results demonstrated that NPs with the crosslinked AIE core structures are a promising luminescent material design motif to realize emission independent on molecular dispersion. 相似文献
A neuritegenic ganglioside from sea cucumber , HLG‐2 (see figure), has been synthesized for the first time. The unique tandem of sialic acids, Neu5Gc‐α(2,4)‐NeuAc, was established by the combination of a reactive N‐Troc sialyl donor and a 1,5‐lactamized sialyl acceptor. The ceramide counterpart was assembled in a stereoselective manner. Direct connection of the trisaccharide and the ceramide successfully afforded a precursor of HLG‐2, which was converted to ganglioside HLG‐2 in pure form.
Two-dimensional turbulence in flowing soap films with polymer additives is analyzed by image analysis. The power spectra of
the interference patterns of turbulent soap films are calculated. The scaling exponent of the power spectrum is −5/3 for polymer
free solution and −1 for dilute polymer solution in enstrophy cascade range, which is consistent with the results of thickness
fluctuations in previous researches. We propose a Curvature analysis method that calculates the curvatures of the interference
pattern of turbulent soap films. The results suggest that the curvature histogram describes well the shape of the interference
pattern, which is related to the shape of the vortices. The curvature histograms for different polymer concentrations can
be fitted by a stretched exponential function. 相似文献
Just after poly(N-isopropylacrylamide) (PNIPA) gels are immersed into hot water over the critical temperature, they undergo a two- or three-step shrinking accompanied with the whitening. The size of gels and the destination temperature were changed and their effects on the shrinking process of PNIPA gels were studied. The following important knowledge in the volume phase transition process of PNIPA gels was obtained. The first is the fact that the fraction of first shrinking is determined by the shrinking rate in the first shrinking stage. The second is the fact that PNIPA gels are divided into small parts by the pinning of density fluctuation in the final stage of the first shrinking and that the shrinking process of each small part undergoes in the secondary shrinking stage. The volume phase transition process of PNIPA gels is briefly discussed from the viewpoint of the scaling theory. 相似文献
A series of coin-type lithium secondary batteries with polyaniline positive electrodes was developed and commercialized which might be not only the first practical polymer battery but also the first industrial application of conducting polymers. Performances of the commercialized batteries were described in detail in this paper. In order to achieve the development the most important thing was the optimization of molecular structure and molphology of multiguise polyaniline as the electrode material. According to the findings obtained during the development, polyaniline sheet was prepared substantially to be composed of imino-1,4-phenylene (IP) and the cation radical of IP (IP+) by the novel procedure, not to include quinoid configuration of polyaniline (NP) which was proved to be electrochemically inactive in non-aqueous systems. 相似文献
Reactions of primary selenoamides with dimethyl acetylenedicarboxylate afforded 2‐aryl‐5‐methoxy‐carbonylmethylene‐4,5‐dihydro‐1,3‐selenazol‐4‐ones in moderate to high yields. Reactions of the primary selenoamides with acetylenedicarboxylic acid gave 2‐aryl‐5‐carboxymethylene‐4‐ethoxy‐4,5‐dihydro‐1,3‐selenazol‐4‐ols in moderate yields. 相似文献
Reactions of isoselenocyanate with methyl aminoacetate hydrochlorides in the presence of triethylamine afforded selenohydantoins, 2‐selenoxoimidazolidin‐4‐ones, in high yields. 相似文献
Originally discovered as a minor by-product of 6-sulfo-N-acetylsialyl Lewisx, the de-N-acetylated form 1 is a superior L-selectin ligand to the N-acetyl form. To substantiate the extraordinary reactivity of 1 , it was synthesized for the first time and its binding to L-selectin investigated. Compound 1 and related structures may be high-affinity endogenous ligands for L-selectin that are involved in the interaction of leukocytes with the vascular endothelium. 相似文献
Thermal stability of syndiotactic polypropene (syn-PP) was investigated by comparison with isotactic polypropene (iso-PP). Heat treatments were carried out in air at 160–220°C for 10–30 min. Under these conditions, molecular weight and molecular weight distribution of syn-PP were almost kept constant, indicating the high stability of syn-PP. Iso-PP was degraded drastically under the same conditions. Thus, it is confirmed that the stereoregularity is one of the dominant factors to determine the stability of PP. 相似文献