Cellulose - Most superabsorbent polymers (SAPs) are prepared based on synthetic polymers (from petroleum resources), making them costly, nondegradable, and not ecofriendly. To overcome these... 相似文献
The purpose of this paper is to fabricate novel nanoparticles (NPs) from a single disulfide bond-bridged block copolymer poly(hydroxyethyl methacrylate)-S-S-polycaprolactone (PHEMA-S-S-PCL). The novel biomaterial was synthesized by ring-opening polymerization and reversible addition–fragmentation chain transfer polymerization. The cargo-free NPs were fabricated with the solvent evaporation method, and studies on NPs' characterizations were carried out. The hydrogen nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy spectra confirmed the synthesis of PHEMA-S-S-PCL copolymer. Thermo-gravimetric analysis curves indicated that the obtained PHEMA-S-S-PCL copolymer had good thermostability. Transmission electron microscopy and dynamic light scatter results suggested that the cargo-free NPs were in round shapes with an average diameter of 103.6 ± 0.12 nm. The low critical micelle concentration of cargo-free NPs (7.9 × 10?4 mg/ml) indicated that these NPs would keep their spherical shapes after being attenuated by abundant liquid (e.g., blood or body fluid). Furthermore, these NPs showed high stability at the presence of bovine serum albumin. Therefore, it could be speculated that these NPs would not be absorbed by proteins in blood, and they could be used as a candidate carrier for drug delivery. 相似文献
Adding insulating polymers to conjugated polymers is an efficient strategy to tailor their mechanical properties for flexible organic electronics. In this work, we selected two insulating polymers as additives for high-performance photoactive layers and investigated the mechanical and photovoltaic properties in organic solar cells (OSCs). The insulating polymers were found to reduce the electron mobilities in the photoactive layers, and hence the power conversion efficiencies were significantly decreased. More importantly, we found that the insulating polymers exhibited negative effect on the mechanical properties of the photoactive layers, with reduced Young's modulus and low crack onset strains. Further studies revealed that the insulating polymers had poor miscibility with the photoactive layers, providing large domains and more cavities in blend thin films, which act as negative effect for the tensile test. The studies indicate that rational selection of insulating polymers, especially enhancing the non-covalent interaction with the photoactive layers, will be critically important for the stretchable OSCs. 相似文献
Zinc molybdate (ZnMoO4), a layer perovskite material, has the advantages of high stability, excellent optical and charge properties. However, its high band gap and high electron–hole recombination efficiency limit its application in the photocatalytic reduction field like hydrogen production. In this study, we used CdS as a co-catalyst and successfully prepared CdS/ZnMoO4 composite photocatalysts with different loadings. The hydrogen evolution rate of CdS/ZnMoO4 reached 530.2 µmol h?1 g?1, which was approximately 11 and 100 times more than rates of pure CdS and ZnMoO4 under the same conditions, respectively. It is the presence of CdS that contributed to this improved performance, which acted as an electron acceptor to separate electrons and holes. Besides, a reasonable mechanism was provided based on photoelectrochemical characterizations. CdS loading greatly improved the hydrogen evolution performance of ZnMoO4 under visible light, providing a direction to improving the performance of perovskite based photocatalysts.
Electrochemical reduction of carbon dioxide into value-added products is a promising way to recycle the greenhouse gas, thus solving the crisis of global warming. Pressing challenges remain in regulating the catalytic selectivity. In this work, we demonstrated a metal-organic frameworks-assisted approach to synthesizing In species loaded on the surface of N doped carbon matrix. By controlling the particle sizes, the catalytic selectivity can be easily altered. The obtained Inc/NC possesses the outstanding capability for converting CO2 into CO. And 80.09% Faraday efficiency (FE) of CO can be achieved at 0.8 V vs. RHE. While the In2O3/C exhibits different catalytic behaviors, the main product is formic acid and the FE is more than 50% at 0.8 V vs. RHE. The selectivity reversal can be attributed to the strong interactions between In clusters and N atoms of carbon supports, which efficiently inhibits the formation of the by-product, formic acid. Our research has paved a new way to modulate catalytic selectivity by manipulating the fine structures of the catalysts. 相似文献
Two-dimensional covalent organic frameworks(2D COFs)bearing various topologies can be precisely designed based on the symmetry of monomers.Their pore environment can be further regulated via either pre-functionalization of the monomers or post-modification of the skeleton.Among them,sub-stoichiometric synthesis is an efficient method which can mediate uncondensed functional moieties periodically arranged in the COF skeletons.Herein,a series of imine-linked 2D COFs with specifically decorated formyl or amino groups were selectively synthesized via sub-stoichiometric formyl transamination.The molar ratios of the monomers directly determine the structures of the resulting COFs with periodic vertex vacancies.The COF with polar amino sites could efficiently capture CO2 and H2O.This work demonstrates tuning the stoichiometry of the monomers could facilely modulate the functions of the pore channels.It also provides insights into constructing novel COFs with complex structures for targeted applications. 相似文献