Hierarchical porous carbons from carboxylated coal-tar pitch functional poly(acrylic acid) hydrogel networks for supercapacitor electrodes.

A gel carbonization strategy for the synthesis of hierarchical porous carbons (HPCs) from carboxylated coal-tar pitches (CCP) functional poly(acrylic acid) (PAA) hydrogel networks for advanced supercapacitor electrodes was reported. The amphiphilic CCP and PAA polymer could be easily self-assembled to gel by the major driving force of hydrogen bonding and π-π stacking. The HPCs containing interconnected macro-/meso-/micropores were fabricated by direct carbonization of the dried hydrogels. The resultant HPCs with a high specific surface area and total pore volume of 1294.6 m2 g-1 and 1.34 cm3 g-1 respectively, as a supercapacitor electrode exhibit a high specific capacitance of 292 F g-1 at 1.0 A g-1 in two-electrode system. The electrode also exhibits ultra-long cycle life with a capacitance retention as high as 94.2% after 10 000 cycles, indicating the good electrochemical stability. Furthermore, the concept of such hierarchical architecture and synthesis strategy would expand to other materials for advanced energy storage systems, such as Na-ion batteries and metal oxides for supercapacitors.

Hierarchical porous carbon derived from carboxylated coal-tar pitch for electrical double-layer capacitors.

Hierarchical porous carbons have been synthesized using amphiphilic carboxylated coal-tar pitch as a precursor via a simple KOH activation process. Amphiphilic carboxylated coal-tar pitch has a high content of hydrophilic carboxyl groups that enable it to be easily wetted in KOH solution and that facilitate the activation process. In the present study, the effect of the activation agent to precursor ratio on the porosity and the specific surface area was studied by nitrogen adsorption-desorption. A maximum specific surface area of 2669.1 m2 g-1 was achieved with a KOH to carboxylated pitch ratio of three and this produced a structure with micropores/mesopores. Among the various hierarchical porous carbons, the sample prepared with an activation agent to precursor ratio of two exhibited the best electrochemical performance as an electrode for an electrical double-layer capacitor in a 6 M KOH electrolyte. The specific capacitance of the sample was 286 F g-1 at a current density of 2 A g-1 and it had a capacitance-retention ratio of 93.9%, even after 10 000 cycles. Thus, hierarchical porous carbons derived from amphiphilic-carboxylated coal-tar pitch represent a promising electrode material for electrical double-layer capacitors.

Dicarbonyl-tuned microstructures of hierarchical porous carbons derived from coal-tar pitch for supercapacitor electrodes.

A simple and effective template-free method to prepare hierarchical porous carbons (HPCs) has been developed by using low-cost coal-tar pitch as a starting material, anhydrous aluminum chloride as the Friedel-Crafts catalyst, and oxalyl chloride as the cross-linking agent. By a simple controllable Friedel-Crafts reaction, diketone-functionalized coal-tar pitch as the hierarchical porous coal-tar pitch precursor was obtained via a one-step carbonization to provide a well-developed micro-mesoporous network. Nitrogen adsorption and desorption measurements showed that the surface area, pore volume, pore size and pore size distributions of the resulting carbon materials was dependent on the usage of the cross-linking agent. The as-fabricated HPCs have a large Brunauer-Emmett-Teller specific surface area of 1394.6 m2 g-1 and exhibit an excellent electrochemical performance with the highest specific capacitance of 317 F g-1 at a current density of 1 A g-1 in a three-electrode system. A symmetric supercapacitor was fabricated from HPC-DK-1.0 in a two-electrode system, which exhibits a high specific capacitance of 276 F g-1 at a current density of 0.25 A g-1, a high rate capability and an excellent cycling stability with a capacitance retention of 92.9% after 10 000 cycles. The one-step carbonization method that produced HPCs for electrical double-layer capacitors represents a new approach for high-performance energy storage.

Amphiphilic tertiary amine N-oxides: a mediated radical emulsion polymerization with non-formation of alkoxyamine dormant chains.

Octadecylamine ethoxylate (EO = 5) N-oxides (AO-1805) were presented which are one kind of interfacial tertiary amine N-oxides that differ from TEMPO derivatives. This method took the advantage of amphiphilic alkyldiethoxylated amine oxide to form micelles, and had novel "living" characteristics based on the non-formation of dormant chains.

Evaluation of poly(D,L-lactide-co-glycolide) microspheres for the lung-targeting of yuanhuacine, a novel DNA topoisomerase I inhibitor.

The present study was intended to develop poly(D,L-lactide-co-glycolide) (PLGA; 50:50, 0.15 dL/g) microspheres (MS) loaded with yuanhuacine (YHC) for passive targeting in lung as well as providing a simple evaluation method for the targeting efficiency of MS. A kind of photochromic spiropyran dye was applied to label MS to clearly demonstrate the in vivo distribution characteristics through intravenous injection into mice and rabbits. Sections of 10-microm thickness from different organs were cut using a microtome, and fluorescent microscopy was used to determine the biodistribution of the MS. The average particle size of MS was 9.0 microm, and the glass transition temperature was 37-40 degrees C. In vitro, the cumulative release achieved 50.8% in 24 h. Histological sections from different organs indicated that the amount of MS in lung achieved maximum in 6 h, as about 8 times as in liver and 70 times higher than the average concentration of other organs. In vivo, MS were gradually swelled and drug concentration remained just 10% in 12 h, which would not result in long time embolization in the lung. This evaluation method supplies a simple and visualized channel in focus for the targeting efficiency of PLGA MS.