A flexible bioelectrode based on IrO2–coated metallized polypropylene micromembrane

We demonstrate the fabrication of a flexible and conductive bioelectrode via the electrodeposition of IrO₂ nanoparticles on a metalized polypropylene micromembrane (PPMM). The metalized PPMM is prepared by carrying out conformal electroless deposition of Au on individual polypropylene (PP) fibers of PPMM using both polydopamine and polyvinyl alcohol as the surface–modifying agents to improve the hydrophilicity of PPMM. Images from scanning and transmission electron microscopes, as well as analysis from energy dispersive X–ray spectrometer and X–ray photoelectron spectroscopy confirm the successful formation of IrO₂ nanoparticles on individual PP fibers of metalized PPMM. For bio–stimulating purpose, the IrO₂–coated PPMM reveals an impressive charge–storage–capacity of 54.6 mC/cm² in cyclic voltammetry, In addition, under a symmetric bi–phasic current pulse, its charge–injection–capacity reaches 466 μC/cm². Since the entire constituents for the IrO₂–coated PPMM are bio−compatible, we envision its potential use as a bioelectrode in implantable biomedical devices.     

Three-dimensional fivefold interpenetrating microporous metal–organic framework based on mixed flexible ligands

The chiral diamondoidlike Cd(II) containing coordination polymer {[Cd(oba)(bib)]·2H₂O}_n (1) (oba = 4,4′-oxybis(benzoate), bib = 1,4-bis(2-methyl-imidazol-1-yl)butane) is reported; the 3D networks interpenetrate fivefold, nevertheless leave cavities capable of including sizable guest molecules. This compound also exhibits high thermal stability and blue-shift emission, and can be explored for potential blue luminescent materials.     

Thiol-ene “clickable” carbon-chain polymers based on diallyl cyclopropane-1,1-dicarboxylate

A novel type of clickable polymers with a very high local density of allyl side groups was developed. These polymers were obtained by the anionic ring-opening (co)polymerization of diallyl cyclopropane-1,1-dicarboxylate using as an initiating system a protic precursor whose acid–base reaction with the t-BuP₄ phosphazene base generated the initiator in situ. The obtained polymers display geminated allyl groups on every third carbon alongside the macromolecular backbone. Homopolymers as well as block and statistical copolymers have been synthesized, with controlled molecular weights and narrow molecular weight distributions. The coupling of mercaptans with the allyl CC double bonds has been investigated both thermally and photochemically, with the influence of the type of initiation on the efficiency of the polymer modification being discussed in comparison with other “clickable” systems. Further functionalization by several thiols was performed, leading to a range of functional poly(cyclopropane-1,1-dicarboxylate)s.     

CEramics based on α-sialon

Ceramics containing pure α-sialon and α-sialon in combination with β-Si₃N₄, produced from two types of silicon nitride powder, are described. It is shown that the high-temperature strength of the ceramics increases with increase in the content of α-sialon in the composition. Data on the microstructure, phase composition, and mechanical characteristics of the synthesized materials are presented.     

Two stacked 2Dchiral/2Dchiral → 2Dachiral sheets based on V-shaped imidazolyl ligand and flexible aliphatic acids

Two new stacked 2D_chiral/2D_chiral → 2D_achiral coordination polymers {[Cd(BIDPE)(pim)]·(H₂O)}_n (1) and {[Cd(BIDPE)(glu)]·(H₂O)}_n (2) were prepared under hydrothermal conditions based on V-shaped ligand 4,4′-bis(imidazol-1-yl)diphenyl ether (BIDPE) and flexible polycarboxylic acids. In addition, the solid-state photoluminescent spectra were measured at room temperature.     

Modification of electrolyte surface with “windows” and “dimples array” structure for SOFC based on YSZ electrolyte

A strategy based on tape-casting and laser micro-processing was proposed to enhance the electrochemical performance of solid oxide fuel cells by modifying the electrolytes with a “windows” structure and a “dimples array” structure. Scanning electron microscopy images of the “windows” structure indicated that the thickness of electrolyte in the thin areas was reduced from 220 µm to 75 µm, resulting in a significant decrease in ohmic resistance by a factor of 1.69 at 800 °C. In addition, three-dimensional profile images of the “dimples array” structure showed a remarkable increase in the electrode/electrolyte interface area that is directly related to the triple-phase boundaries. Furthermore, following the modifications in this work, the optimal cell in this study achieved an encouraging performance relative to that of the reference cell, with the peak power density increasing by a factor of 1.63 at 800 °C. These results implied that effective structural modification may be a promising approach for improving cell performance.     

Effect of a formulation named “Giral” on mechanical properties of a composite based on silica and unsaturated polyester resin

To improve the performances of a composite based on silica and unsaturated polyester resin, modification of silica surface and addition of a dispersing agent are required. The surface of raw silica was modified with vinyltrimethoxysilane in acidic conditions, adding methacrylic acid. Moreover, to enhance the compatibility between silica and polyester resin, a block copolymer which reacts as a dispersing agent was added. The mixture of these components is named “Giral.” The mechanism of interaction of the different components of the “Giral” with the raw silica is described. Adding this formulation to a mixture of polyester resin and silica leads to a decrease of the viscosity of the polyester resin/silica system and the mechanical properties of the composite thus formed are improved.     

Nonlinear optic polymer film based on cellulose derivativer

纤维素衍生物基非线性光学聚合物膜周立民,王得宁(华东理工大学材料科学与工程学院,上海200237)以二乙酸纤维素为基础聚合物,三羟甲基三聚氰胺(TMM)或六羟甲基三聚氰胺(HMM)为交联剂,制得含正离子生色团的二阶非线性光学聚合物。结果表明,以HMM为交联剂制得的非线性光学聚合物的驰豫行为强于采用TMM者,这与小分子物质的存在及HMM的自缩合能力较强有关。     

Interpenetrating polymer networks based on uralkyd–butylmethacrylate

Two-component semi- and full-interpenetrating polymer networks (IPNs) of hydrogenated castor oil based uralkyd resin (UA) and poly(butylmethacrylate) (PBMA) were synthesized by the sequential technique. The elastomers obtained were characterized with respect to their mechanical properties such as tensile strength, elongation at break and hardness (Shore A). The apparent densities of these samples were determined and compared. Glass transition studies were carried out using differential scanning calorimetry. The thermal characterization of the elastomers was undertaken with the aid of thermogravimetric analysis. Phase morphology was studied by scanning electron microscopy. The effect of the variations of UA–PBMA on the above-mentioned properties was examined. The elongation percentage at break showed higher values in the case of all the semi-IPNs as compared to the full-IPNs.     

Ceramic varistors based on ZnO–SnO2

Model ceramic varistor formulations based on 98% ZnO–SnO₂ (plus 2% oxides of Bi, Co and Mn) were prepared by conventional powder processing routes; specimens were sintered at 1150–1275 °C. The product density increased with SnO₂ content, but decreased with increase in sintering temperature. The microstructures contained ZnO, Zn₂SnO₄ spinel and very small bismuth rich phases; with increasing Sn content the spinel became the dominant phase. From I–V measurements, the non-linear coefficients were found to be in the range 24–32. For all compositions, the α values decreased with increasing sintering temperature; the maximum α value was obtained with samples containing 20 mol% SnO₂ sintered at 1200 °C. Breakdown fields were in the range 3000–11000 V/cm and increased with increasing tin content. Leakage currents were in the range 1–11 μA. Tin substitution for Zn appears to cause a strong donor effect.     

Novel cell-penetrating peptides based on α-aminoxy acids

The remarkable ability of cell-penetrating peptides (CPPs) to deliver cell-impermeable compounds into living cells makes them attractive transporters for use in biology and medicine. Despite their highly efficient cellular uptake, CPPs consisting of natural amino acids always suffer from degradation and endosomal entrapment, thereby greatly limiting their application in vivo. Here, we describe the preparation of novel CPPs incorporating α-aminoxy acid residues and their cellular uptake behavior. We demonstrate that introducing α-aminoxy acids into the backbones of CPPs enhances their diffuse cytosolic distribution after direct membrane translocation. We also reveal a hybrid peptide, consisting of D-α-aminoxy acids and L-α-amino acids, that achieves efficient diffuse distribution in the cytosol, is stable toward serum, and possesses low cytotoxicity, thus making it a possible vector candidate for in vivo applications. Our results confirm that α-aminoxy acids are useful building blocks when designing novel CPPs possessing favorable properties.     

Fabrication of thermo-sensitive optical switches based on lanthanide-polyoxometalates and their “on-off” luminescence controlled by temperature

The temperature-responsive luminescent nanocomposites were prepared by the combination of poly (N-isopropylacrylamide) (PNIPAM) with lanthanide-polyoxometalates/SiO₂ spheres, exhibiting controlled reversible luminescent behavior with change in temperature. The structures and properties of nanocomposites were characterized by transmission electron microscopy, scanning electron microscope, FT-IR, UV-vis, dynamic light scattering and luminescence spectra. The research shows that the nanocomposites in aqueous solution display “on–off” luminescence by simple temperature stimuli. For example, the hybrid nanocomposites of PNIPAM/Eu-polyoxometalate/SiO₂ in aqueous solution show bright red luminescence under UV light, which could be observed by the naked eye when the temperature is below the lower critical solution temperature (LCST), showing the “on” state. However, the red luminescence of nanocomposites in aqueous solution is significantly decreased when temperature is above LCST, showing the “off” state.     

New highly conductive organic–inorganic hybrid electrolytes based on star-branched silica based architectures

A new type of organic–inorganic hybrid electrolyte has been developed by a sol–gel process through the reaction of cyanuric chloride with poly(oxyalkylene) diamine and 3-isocyanatepropyltriethoxysilane, followed by co-condensation of 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane. A maximum ionic conductivity of 1.0 × 10^?4 Scm^?1 at 30 °C has been achieved with the solid hybrid electrolyte. The results of solid-state NMR not only confirm the structural framework of the hybrids, but also provide a microscopic view of the effects of salt concentrations on the dynamic behavior of the polymer chains. The hybrid materials are blended with PVdF-HFP to form the blend hybrid membrane, followed by plasticization with various electrolyte solvents, with the purpose of increasing ionic conductivity. The plasticized blend hybrid electrolyte exhibits a maximum room temperature ionic conductivity of 8.8 × 10^?3 Scm^?1. Such a high ionic conductivity allows it as a potential candidate for applications in lithium ion batteries.     

“Liquid-cristalline” gels of polyamide networks with stiff segments and flexible junctions

Summary The preparation of a novel family of liquid-crystalline polyamide network gels is described. In these networks, the segments are stiff and longer than the critical axial ratio for mesomorphic behavior. The junctions are trifunctional and flexible. The gels are intensely birefringent in the relaxed nascent state, unlike fully rigid or fully flexible gels. The birefringence of the present gels is clearly associated with the coexistence in them of both long, stiff mesogenic segments and flexible trifurcated junctions. Thermal studies of the gels indicate very strong attractive interactions between the networks and the solvent.     

Discussion of “Numerical simulation of moisture transport in concrete based on a pore size distribution model”

This paper presents a discussion on a recent article authored by Huang et al. [Numerical simulation of moisture transport in concrete based on a pore size distribution model, Cement and Concrete Research 67 (2015) 31–43].     

Design of an “all solid-state” supercapacitor based on phosphoric acid doped polybenzimidazole (PBI) electrolyte

The effectiveness of phosphoric acid doped polybenzimidazole as a polymer electrolyte membrane to fabricate an all solid-state super capacitor has been explored using hydrous RuO₂/carbon composite electrodes (20 wt.%) of surface area 250 m² g⁻¹ with many intrinsic advantages. The electrochemical evaluation of these super capacitors through cyclic voltammetry, charge/discharge and impedance measurements demonstrate the utility of this type of thin, compact and flexible supercapacitor capable of functioning at 150 °C to yield a maximum capacitance of about 290 F g⁻¹ along with a life of more than 1,000 cycles. A power density of 300 W kg⁻¹ and energy density of 10 Wh kg⁻¹ have been accomplished although the equivalent series resistance (ESR) of about 3.7 Ω needs to be reduced further for high rated applications.     

A colorimetric and “turn-on” fluorescent chemosensor for Zn(II) based on coumarin Shiff-base derivative

A coumarin Shiff-base derivative, 7-hydroxy-3-(2-hydroxybenzylideneamino)-2H-chromen-2-one (CSB), was obtained by simple two-step organic synthesis from cheap and commercially available starting materials. CSB has nearly no fluorescence in CH₃CN solution. However, in the presence of Zn(II) ion, a “turn-on” fluorescence was observed. Other metal ions in CSB solution show very little emission or do not show any emission. CSB can also be used as a colorimetric chemosensor for Zn(II), which is easily observed from colorless to yellow by the naked eye. The absorption maximum of CSB shows a large red shift from 374 to 452 nm upon addition of Zn(II).     

Antimicrobial and biodegradable materials based on ε-caprolactone derivatives

Appropriate wound care is pivotal in preventing wound and postsurgery infections, which remain a serious clinical problem. In this study, we report the successful fabrication of antimicrobial and biodegradable materials for possible use in the medical field. Amino functionalized polycaprolactone (PCL [Poly(CL-co-ACL)]) was synthesized via ring opening polymerization. This polymer was then functionalized via the pendant amine to induce antimicrobial efficacy. This was done through the grafting of poly(lysine) onto the amine as well as the quaternization of the amine using alkyl halides. The chemical structures of the synthesized monomers and polymers were confirmed using nuclear magnetic resonance (¹H NMR and ¹³C NMR) spectroscopy and attenuated total reflection-Fourier transform infrared spectroscopy. The molecular weights of the polymers were determined using gel permeation chromatography. Nanofibre scaffolds were produced from the polymers using the electrospinning technique and these were characterized though scanning electron microscopy. The antimicrobial efficacy of the fabricated materials was tested against the Gram-positive (Staphylococcus aureus ATCC 25923) and Gram-negative (Pseudomonas aeruginosa ATCC 27853) bacteria using the disc diffusion and shake flask methods. The polymers demonstrated excellent antimicrobial efficacy. The fibers were exceptionally biodegradable which opens a lot of applications in the biomedical space.