Latest ArticlesWith the rapid growth in electronic device performance, there has been an increasing demand for thermally conductive polymer composites to handle the thermal management issue, thus contributing to the great importance to develop the graphene framework, which is evaluated as the most promising reinforcements for enhancing the thermal conductivity of polymer. Vacuum filtration is a common method to fabricate graphene framework, whereas, it is available to prepare a framework with centimeter-scale thickness by filtrating the graphene-water dispersion, due to the fact of sample cracking caused by the mismatch of surface tension between graphene and water. In this work, a surfactantassisted strategy was proposed by adjusting the surface tension of the water close to that of graphene first, then performing a conventional filtration process, to fabricate graphene framework. As a result, a thick graphene framework (thickness: 3 cm) was successfully prepared, and after embedding into epoxy, the framework endows the composite (13.6 wt%) with a high in-plane thermal conductivities of 12.4 W/mK, which is equivalent to ≈64 times higher than that of neat epoxy. Our method is simple and compatible with the conventional filtration process, suggesting great potential for the mass-production of graphene framework to meet the practical application requirements.
Supramolecular polymers constructed by orthogonal self-assembly based on multiple hydrogen bonding and macrocyclic host-guest interactions have received increasing attention due to their elegant structures, outstanding properties, and potential applications. Hydrogen bonding endows these supramolecular polymers with good adaptability and reversibility, while macrocyclic host-guest interactions give them good selectivity and versatile stimuli-responsiveness. Therefore, functional supramolecular polymers fabricated by these two highly specific, noninterfering interactions in an orthogonal way have shown wide applications in the fields of molecular machines, electronics, soft materials, etc. In this review, we discuss the recent advances of functional supramolecular polymers fabricated by orthogonal self-assembly based on multiple hydrogen bonding and host-guest interactions. In particular, we focus on crown ether- and pillar[n]arene-based supramolecular polymers due to their compatibility with multiple hydrogen bonds in organic solution. The fabrication strategies, interesting properties, and potential applications of these advanced supramolecular materials are mainly concerned.
Two A-B-C type conjugated amphiphilic triblock fullerene derivatives C60-2HMTPB and C60-2EHTPB were obtained in multi steps synthesis with three different blocks, and the amphiphilic diblock molecular C60-4TPB was also preferred as a reference. When as modifying layer on zinc oxide (ZnO), the three fullerene derivatives can all reduce the work function of ZnO via modulation of the interfacial dipoles and lead a better electrical coupling. As introducing treatment of toluene, the obvious self-assembly of fullerene derivatives were observed, which were supported by X-ray diffraction and contact angle of water measurement. Base on PTB7-Th:PC71BM system, the inverted organic solar cells devices with structure of ITO/ZnO/fullerene derivatives/PTB7-Th:PC71BM/MoO3/Al got power conversion efficiencies of 8.62%, 8.83% and 9.00% for C60-4TPB, C60-2HMTPB and C60-2EHTPB, respectively, compared 8.13% of devices with bare ZnO. The result of conjugated amphiphilic triblock fullerene derivatives provides a straightforward approaching by simultaneously modulating the morphology and interfacial work function of ZnO, which can also lead high performance in optoelectronic devices.
Cysteine chemistry provides a low cost and convenient way for site-specific protein modification. However, recombinant expression of disulfide bonding containing protein with unpaired cysteine is technically challenging and the resulting protein often suffers from significantly reduced yield and activity. Here we used genetic code expansion technique to introduce a surface exposed self-paired dithiol functional group into proteins, which can be selectively reduced to afford active thiols. Two compounds containing self-paired disulfides were synthesized, and their genetic incorporations were validated using green fluorescent proteins (GFP). The compatibility of these self-paired di-thiols with natural disulfide bond was demonstrated using antibody fragment to afford site-specifically labeled antibody. This work provides another valuable building block into the chemical tool-box for site-specific labeling of proteins containing internal disulfides.
Polymeric carbon nitride (CN) semiconductor by thermal condensation of N-rich precursors has attracted much attention for its capability ranging from photocatalytic and photoelectrochemical energy conversion to biosensing. However, the influence of condensation process on the final structure of CN was rarely studied, making the condensation kinetic far from be fully optimized. Herein, we report the preparation of CN by a simple condensation kinetics modulation using a faster ramping rate during the polymerization process. The modified condensation recipe was even simpler than the conventional one, but led to an improved photocatalytic H2 evolution up to 3 times without any additional chemicals or other complements. Detailed mechanism studies revealed the increase of crystallinity and surface area due to the rapid condensation played the key roles. This work would offer a more facile and effective way to prepare bulk CN for large-scale industrial applications of bulk CN with higher photocatalytic actives for sustainable energy, environmental and biosensing.
To find potential zeolitic imidazolate frameworks (ZIFs) for CO2 capture from flue gas, we built 169, 898 ZIF models from 84, 949 hypothetical zeolite networks. By calculating their lattice energies, accessible volumes to CO2, the isosteric adsorption heat (Qst) of H2O, Henry's constant ratio (SKH) of CO2/N2, percent regenerability (R%), CO2 working capacity (ΔNCO2), CO2/N2 adsorption selectivity (SCO2/N2) and adsorbent performance score (APS), we identified 49 hydrophobic ZIF structures that might outplay already-realised ZIFs built from the same imidazolate linkers for CO2 capture from flue gas.
We describe a simple method to prepare magnetic responsive polydivinylbenzene (PDVB) nanofiber composites by precipitated cationic living polymerization in the present of oleic acid capped Fe3O4 nanoparticles (NPs). The Fe3O4 NPs are encapsulated with the PDVB forming dendrites, from which thin nanofibers are grown in the tip-growth mode. The thin nanofibers are interwoven with the thick nanofibers forming robust composite network. The composites are magnetic responsive and highly efficient to gel almost all chemicals. Separation of the gelled chemicals from water becomes easier with a magnet. The performance is promising for magnetic collection of chemical spills.
Three new rare cyclopiane diterpenes (1-3), together with thirteen known compounds (4-16), were isolated and identified from a sea sediment-derived fungus Penicillium sp. TJ403-2. The planar and relative structures of compounds 1-3 were elucidated by HRESIMS, one- and two-dimensional NMR analyses, and their absolute configurations were further established by X-ray crystallography experiment. Compounds 1-3 were evaluated for the antiinflammatory activity against LPS-induced NO production, and compound 1 showed notable inhibitory potency with an IC50 value of 2.19±0.25 μmol/L, which was three fold lower than the positive control indomethacin (IC50=8.76±0.92 μmol/L). Further Western blot and immunofluorescence experiments demonstrated its mechanism of action to be that 1 inhibited the NF-ΚB-activated pathway, highlighting it as a promising starting point for the development of new antiinflammatory agents.
In clinical cancer research, it is quite promising to develop multimodal synergistic therapeutic strategies. Photodynamic and photothermal synergistic therapy is a very desirable multimodal therapy strategy. Herein, we report a facile and simple method to construct a nanotherapeutic agent for photodynamic and photothermal therapy. This nanotherapeutic agent (ZnO@Ce6-PDA) is composed of a ZnO nanoparticle core, an interlayer of photosensitizer chlorin e6 (Ce6) and an outer layer of polydopamine (PDA). Due to the existence of Ce6, the ZnO@Ce6-PDA can efficiently generate singlet oxygen (1O2) under 660 nm laser irradiation. Moreover, the ZnO@Ce6-PDA can serve as a photothermal agent, because of the excellent photothermal conversion efficiency of the PDA coating layer in the presence of 780 nm laser. Experiment results demonstrated that the designed nanotherapeutic agent had outstanding phototoxicity upon the combination of laser irradiation at 660 and 780 nm. Thus, our work proves that the ZnO@Ce6-PDA is a promising photodynamic/photothermal dual-modal nanotherapeutic agent for enhanced cancer therapy.
In this manuscript, we first report an ultrasensitive detection assay of microRNA by combing asymmetric polymerase chain reaction (A-PCR) and loop-mediated isothermal amplification (LAMP) technology. Using A-PCR obtained an extended single strand to form LAMP stem-loop structure under isothermal amplification conditions. We used miRNAs as a loop primer probe in LAMP reaction and completed its ultrasensitive and rapid detection. The established method furnished a fast, specific and efficient detection of target miRNA with a detection limit as low as 10 amol/L in 90 min.