Hydrogel electrolytes are of particular interest in the fabrication of flexible supercapacitors that are able to withstand deformation and physical damage. Nevertheless, there still exists a huge space in the design of hydrogel electrolytes with comprehensive performances including high processability, conductivity, mechanical strength, and self-healability. Herein, a slidable polymer network is constructed through the cross-linking reaction among commercially available polyethyleneimine (PEI), polyvinyl alcohol (PVA), and 4-formylphenylboronic acid (Bn) to generate PEI–PVA–Bn hydrogels, which have high adaptability to various electrolytes such as LiCl, NaCl, KCl, and ionic liquids. The as formed hydrogel electrolytes not only show excellent mechanical property (elongation at break up to 1223%, strength of 34.6 kPa) and self-healability (highest strain self-healing efficiency reaches 94.3% within 2 min) but also exhibit high conductivity (up to 21.49 mS cm–1). Flexible supercapacitors constructed by sandwiching the PEI–PVA–Bn-LiCl hydrogel electrolyte between two multiwalled carbon nanotube electrodes demonstrate a broadened operating potential window of 1.4 V, specific capacitance of 16.7 mF cm–2, high cycling stability up to 10 000 charge/discharge cycles, and excellent mechanical stability.
The design of nanoscale drug delivery systems for the targeted codelivery of multiple therapeutic drugs still remains a formidable challenge (ACS Nano, 2013, 7, 9558–9570; ACS Nano, 2013, 7, 9518–9525). In this article, both mitomycin C (MMC) and methotrexate (MTX) loaded DSPE-PEG micelles (MTX–M–MMC) were prepared by self-assembly using the dialysis technique, in which MMC–soybean phosphatidylcholine complex (drug–phospholipid complex) was encapsulated within MTX-functionalized DSPE-PEG micelles. MTX–M–MMC could coordinate an early phase active targeting effect with a late-phase synergistic anticancer effect and enable a multiple-responsive controlled release of both drugs (MMC was released in a pH-dependent pattern, while MTX was released in a protease-dependent pattern). Furthermore, MTX–M–MMC could codeliver both drugs to significantly enhance the cellular uptake, intracellular delivery, cytotoxicity, and apoptosis in vitro and improve the tumor accumulation and penetration and anticancer effect in vivo compared with either both free drugs treatment or individual free drug treatment. To our knowledge, this work provided the first example of the systemically administrated, orthogonally functionalized, and self-assisted nanoscale micelles for targeted combination cancer chemotherapy. The highly convergent therapeutic strategy opened the door to more simplified, efficient, and flexible nanoscale drug delivery systems.
Abstract In this paper, a silicon‐oxygen coupling agent (MPS) with a double bond is hydrolyzed with graphene oxide (GO) to obtain MPS‐GO. The polymerization of MPS‐GO with the phosphorus‐containing monomer (HEPO) is initiated with 2,2′‐Azobis(2‐methylpropionitrile) (AIBN) to obtain multi‐elements hybrid polymer brushes grafting graphene oxide (HM‐GO). As a flame retardant, different amounts of HM‐GO are added to obtain EP composites. In this system, the properties of composite flame retardant obviously increase with the increasing of HM‐GO. The limiting oxygen index (LOI) value of composites with 4 wt% addition of HM‐GO is 31.0%, while the LOI value of EP‐0 is only 23.9%. And the peak heat release rate (PHRR) value is reduced from 515.8 W g −1 of pure epoxy resin to 376.9 W g −1 . In addition, with the increase of HM‐GO addition, the T g value, flexural strength and flexural modulus of EP composites are improved. Through calculation, it is proved that the rising of T g was due to the increase of crosslink density of the system. The flame retardant performance and mechanical properties of the composite materials are steadily improved, indicating that such flame retardants are dispersed well in the epoxy resin. HM‐GO is an efficient macromolecular modified graphene oxide halogen‐free flame retardant, which can improve both flame retardant properties and mechanical properties.
A facile and large-scale method combining airflow-controlled solvent evaporation and amphiphilic copolymer self-assembly has been developed for the generation of hollow polymer microspheres, colloidosomes or even organic–inorganic hybrid colloidosomes. By replacing traditional agitation with the controllable airflow, this surfactant free route showed promising prospect in the fabrication of microcapsules with closed pore morphology. While the hollow polymer microspheres had an adjustable pore structure, the polymer colloidosomes and the hybrid colloidosomes possessed seamless surfaces, making them suitable for the stable encapsulation of small molecules. The hybrid colloidosomes constructed from polymer and Fe3O4 nanoparticles, and the ternary hybrid colloidosomes derived from polymer, polymer nanospheres and Fe3O4 nanoparticles displayed superparamagnetic properties and were excellent contrast agents for magnetic resonance imaging. More importantly, both hybrid colloidosomes and ternary hybrid colloidosomes exhibited a significant evolution of pore morphology from a closed pore structure to an open pore structure in response to the temperature variation, which induced a controllable release of guest molecules.
Controlled polystyrenes with different molar mass values were synthesized starting from benzoyl peroxide and TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxy). The polystyrene homopolymers served as macroinitiators for the block copolymerizations of the dissimilar vinyl monomers butyl methacrylate (BMA), ethyl methacrylate (EMA), methyl methacrylate (MMA), octyl methacrylate (OMA), vinyl acetate (VAc), N,N-dimethylacrylamide (DMA), and 2-(dimethylamino)ethyl acrylate (DAEA). Polystyrene−polymethacrylate diblock copolymers with well-defined structures as well as controlled and narrow molar mass distribution were obtained from the lower-mass polystyrene macroinitiator. Contrary to methacrylates, VAc and DAEA are not readily initiated by the polystyrene macroinitiator. Block copolymer formation was confirmed by 1H NMR and GPC measurements. On the basis of the 1H NMR investigation, there is strong evidence for the presence of TEMPO-terminated copolymers. The TEMPO-mediated polymerization is suitable for the synthesis of polystyrene−polymethacrylate diblock copolymers from vinyl monomers.
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