The self-assembly of block copolymers (BCPs) in the presence of crystallization as the second driving force is reviewed, for BCPs in the bulk, thin films, single crystals and micelles. The ...crystallization of semicrystalline BCPs in the bulk is introduced briefly and the unique morphologies of semicrystalline BCPs at various levels due to crystallization are discussed. The thin film morphologies shown by crystalline BCPs are summarized in terms of the factors affecting the relative strengths of various driving forces. Special attention is paid to the thin film morphologies of functional BCPs containing crystalline poly(3-alkylthiophene) and perylene bisimide units. The single crystal morphologies of semicrystalline BCPs are also presented. Finally, the micellar morphologies of BCPs with a semicrystalline core are reviewed. The controlled and living growth of crystalline micelles, which is the unique characteristic of such micelle, is then discussed.
Materials with tunable long persistent luminescence (LPL) properties have wide applications in security signs, anti‐counterfeiting, data encrypting, and other fields. However, the majority of ...reported tunable LPL materials are pure organic molecules or polymers. Herein, a series of metal‐organic coordination polymers displaying color‐tunable LPL were synthesized by the self‐assembly of HTzPTpy ligand with different cadmium halides (X=Cl, Br, and I). In the solid state, their LPL emission colors can be tuned by the time‐evolution, as well as excitation and temperature variation, realizing multi‐mode dynamic color tuning from green to yellow or green to red, and are the first such examples in single‐component coordination polymer materials. Single‐crystal X‐ray diffraction analysis and theoretical calculations reveal that the modification of LPL is due to the balanced action from single molecule and aggregate triplet excited states caused by an external heavy‐atom effect. The results show that the rational introduction of different halide anions into coordination polymers can realize multi‐color LPL.
By delicate design of coordination polymers incorporating different halogens, multi‐mode color‐tunable long persistent luminescence (LPL) from green to yellow or green to red was possible. The LPL emission colors can be tuned by time, excitation, and temperature, revealing the counter‐balanced mechanisms from single‐molecule and aggregate triplet excited states resulting from an external heavy‐atom effect.
Recombinant human erythropoietin (rhuEPO) has been extensively used as a pharmaceutical product for treating anemia in the clinic. Glycosylation of rhuEPO was crucial for affecting biological ...activity, immunogenicity, and pharmacokinetics. Because of the heterogeneity of glycan, the structure of rhuEPO was complex with several isoforms. Characterization of isoforms was important for quality control of rhuEPO. Here, an improved cIEF method has been established and validated. A polarity‐reversed focusing step was used by reversing both the polarity of the voltage and the catholyte and anolyte vials. A weak base (100 mM ammonium hydroxide solution) was used as a chemical mobilizer to make the acidic bands mobilize stably to the detection window. Compared with CZE method in European Pharmacopoeia, the numbers of isoforms and their peak area percentage were highly consistent. Better reproducibility and higher resolution have been obtained by the improved cIEF method. Moreover, in improved cIEF method, the isoelectric points (pI) of each isoform can be calculated and used for identification. It was also the first time that the cIEF method was fully validated for rhuEPO analysis according to the International Conference on Harmonization (ICH) guidelines.
The most daunting challenge of solid polymer electrolytes (SPEs) is the development of materials with simultaneously high ionic conductivity and mechanical strength. Herein, SPEs of lithium ...bis‐(trifluoromethanesulfonyl)imide (LiTFSI)‐doped poly(propylene monothiocarbonate)‐b‐poly(ethylene oxide) (PPMTC‐b‐PEO) block copolymers (BCPs) with both blocks associating with Li+ ions are prepared. It is found that the PPMTC‐b‐PEO/LiTFSI electrolytes with double conductive phases exhibit much higher ionic conductivity (2 × 10−4 S cm−1 at r.t.) than the BCP electrolytes with a single conductive phase. Concurrently, the storage moduli of PPMTCn‐b‐PEO44/LiTFSI electrolytes are ≈1–4 orders of magnitude higher than that of the neat PEO/LiTFSI electrolytes. Therefore, simultaneous improvement of ionic conductivity and mechanical properties is achieved by construction of a microphase‐separated and disordered structure with double conductive phases.
Solid polymer electrolytes (SPEs) of lithium bis‐(trifluoromethanesulfonyl)imide‐doped poly(propylene monothiocarbonate)‐b‐poly(ethylene oxide) block copolymers are successfully fabricated. SPEs with simultaneously improved ionic conductivity and storage moduli are achieved by construction of a microphase‐separated and disordered structure with double conductive phases, offering an effective strategy for the design of SPEs with optimized and balanced properties for advanced lithium battery technology.
Fascioliasis is a common parasitic disease in livestock in China. However, human fascioliasis is rarely reported in the country. Here we describe an outbreak of human fascioliasis in Yunnan province. ...We reviewed the complete clinical records of 29 patients and performed an epidemiological investigation on the general human population and animals in the outbreak locality. Our findings support an outbreak due to Fasciola gigantica with a peak in late November, 2011. The most common symptoms were remittent fever, epigastric tenderness, and hepatalgia. Eosinophilia and tunnel-like lesions in ultrasound imaging in the liver were also commonly seen. Significant improvement of patients' condition was achieved by administration of triclabendazole®. Fasciola spp. were discovered in local cattle (28.6%) and goats (26.0%). Molecular evidence showed a coexistence of F. gigantica and F. hepatica. However, all eggs seen in humans were confirmed to be F. gigantica. Herb (Houttuynia cordata) was most likely the source of infections. Our findings indicate that human fascioliasis is a neglected disease in China. The distribution of triclabendazole®, the only efficacious drug against human fascioliasis, should be promoted.
Poly(ethylene oxide)‐b‐poly(4‐vinylpyridine) (PEO‐b‐P4VP) block copolymers (BCPs) exhibiting lower disorder‐to‐order transition (LDOT) phase behavior are doped with different salts (LiCl, CuCl2, and ...FeCl3), in which both blocks can competitively associate with the metal ions. It is found that the entropy‐driven LDOT phase behavior of PEO‐b‐P4VP can be bi‐directionally adjusted by enthalpic interactions, depending on the complexation selectivity of metal ions toward two blocks and doping ratio (r). At low rs, Li+ ions preferentially interact with PEO block, leading to a decreased disorder‐to‐order transition temperature (TDOT). Cu2+ ions selectively complex with the P4VP block, and the TDOT first increases with increasing r, followed by a decrease. By contrast, Fe3+ ions interact strongly with both blocks, resulting in increase of TDOT. At high rs, the complexation selectivity becomes weaker, leading to reduced immiscibility and increased TDOT, as compared with the hybrids with low rs. The effects of metal cation and r on the LDOT phase behavior are qualitatively explained by the change of the Flory–Huggins parameter.
The entropy‐driven lower disorder‐to‐order transition (LDOT) of poly(ethylene oxide)‐b‐poly(4‐vinylpyridine) (PEO‐b‐P4VP) is regulated by salt‐doping, i.e., enthalpic interaction. The transition temperature can be bi‐directionally adjusted due to the competitive complexation of metal ions with the PEO and P4VP blocks. This provides a more direct and convenient avenue to regulate the LDOT phase behavior of block copolymers.
This review highlights recent advances in the synthesis of carbon dioxide (CO2)-based copolymers with both linear (di-, tri-, and multi-block, etc.) and non-linear (star-block and grafting) ...architectures. The corresponding catalytic systems are summarized. The microstructure and polymerization mechanism of various types of CO2-based copolymers, including block polycarbonates and block copolymers of polycarbonate with polyester, polyether, polyvinyl, and polydiene are discussed. The junction unit between two blocks, which indicates an abrupt change in the chain microstructure and property, is emphasized to define the microstructure of CO2-based block copolymers. Special attention was paid to one-pot terpolymerization for the synthesis of CO2-based block and grafting copolymers. Finally, the thermal, mechanical, and degradation properties and self-assembly of CO2-based block and grafting copolymers are reviewed. Prospective future research and applications of this new class of polymeric materials are discussed.
In this article, ABA triblock copolymer (tri-BCP) thermoplastic elastomers with poly(ethylene oxide) (PEO) middle block and polyzwitterionic poly(4-vinylpyridine) propane-1-sulfonate (PVPS) outer ...blocks were synthesized. The PVPS
PEO
PVPS tri-BCPs were doped with lithium bis-(trifluoromethane-sulfonyl) imide (LiTFSI) and used as solid polyelectrolytes (SPEs). The thermal properties and microphase separation behavior of the tri-BCP/LiTFSI hybrids were studied. Small-angle X-ray scattering (SAXS) results revealed that all tri-BCPs formed asymmetric lamellar structures in the range of PVPS volume fractions from 12.9% to 26.1%. The microphase separation strength was enhanced with increasing the PVPS fraction (
) but was weakened as the doping ratio increased, which affected the thermal properties of the hybrids, such as melting temperature and glass transition temperature, to some extent. As compared with the PEO/LiTFSI hybrids, the PVPS
PEO
PVPS/LiTFSI hybrids could achieve both higher modulus and higher ionic conductivity, which were attributed to the physical crosslinking and the assistance in dissociation of Li
ions by the PVPS blocks, respectively. On the basis of excellent electrical and mechanical performances, the PVPS
PEO
PVPS/LiTFSI hybrids can potentially be used as solid electrolytes in lithium-ion batteries.
Abstract Hybrid single crystals (HSCs) of different poly( ε ‐caprolactone) (PCL) homopolymers with a poly( ε ‐caprolactone)‐ b ‐poly(ethylene oxide) (PCL‐ b ‐PEO) block copolymer (BCP) are prepared. ...The effects of PCL length, PCL/PCL‐ b ‐PEO molar ratio, crystallization temperature ( T c ), and solvent on crystal morphology are investigated. The optimal T c for the formation of more perfect HSCs is between those for homocrystals of individual PCL and PCL‐ b ‐PEO and roughly increases with the length of PCL and PCL/PCL‐ b ‐PEO molar ratio. The chain folding in the HSCs is studied by comparing the experimentally measured heights obtained by atomic force microscopy (AFM) and theoretically calculated ones based on a sandwich structure model. Under most situations, the PCL homopolymers adopt a larger chain folding number in the HSCs than that in their homocrystals, while the chain folding of BCP remains unaltered. However, when both PCL homopolymer and PCL‐ b ‐PEO BCP crystallize slowly and the overcrowding of the PEO is effectively alleviated, thicker HSCs can be formed, in which the PCL homopolymer preserves the chain folding in its homocrystals but the BCP adopts a reduced chain folding number as compared with that in its homocrystals. The relative crystallization rate of PCL homopolymer versus BCP also affects the real composition and overall height of the HSCs.
Norfloxacin (NOR) is applied clinically to treat keratitis. However, NOR has brought severe side-effects for human corneal epithelium (HCEP) due to overdose and potential toxicity. In this study, two ...in vitro experimental models including monolayer HCEP cells and tissue-engineered human corneal epithelium (TE-HCEP) were used to explore the cytotoxicity and its related mechanisms. The HCEP cells treated with NOR at concentrations from 0.1875 to 3.0 mg/mL displayed abnormal morphology, declined viability, and increased plasma membrane permeability. Moreover, 0.75 mg/mL NOR induced chromatin condensation, S phase arrest, phosphatidylserine externalization, and formation of apoptotic body through activation of caspase-2/−8/−9/−3, downregulation of Bcl-2 and Bcl-xL, upregulation of Bad and Bax, mitochondrial transmembrane potential disruption and release of cytochrome c and apoptosis inducing factor into cytosol, whereas 1.5 mg/mL and 3.0 mg/mL NOR upregulated the expressions of receptor-interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain-like (MLKL) together with inactivation of caspase-2/−8. Furthermore, 0.1875–3.0 mg/mL NOR destroyed the multilayer structure of TE-HCEP model due to a dose-dependent cytotoxicity, which validated the above results. Overall, low-dose (0.1875–0.75 mg/mL) NOR induced apoptosis through mitochondrion-dependent and death receptor-mediated pathways, and high-dose (1.5–3.0 mg/mL) NOR triggered necroptosis via RIPK1-RIPK3-MLKL cascade in HCEP cells.
Display omitted
•Norfloxacin (NOR) showed dose- and time-dependent cytotoxic effects on human corneal epithelial cells.•Low-dose (0.1875-0.75 mg/mL) NOR induced apoptosis through mitochondrion-dependent and death receptor-mediated pathways.•High-dose (1.5-3.0 mg/mL) NOR triggered necroptosis via RIPK1-RIPK3-MLKL cascade.
PDF
