MOP-18-Derived CuO Fiber for Hybrid Supercapacitor Electrodes.

This study explores a simple method of fabricating hybrid supercapacitor electrodes, which could potentially broaden the application of this technology. The method involves electrospinning a uniform solution of Matrimid/Metal-Organic Polyhedra 18 (MOP-18) followed by carbonization at a relatively low temperature of 700 °C in air, rather than in an inert atmosphere, to create free-standing, redox-active hybrid supercapacitor electrodes. Additionally, the synthesis procedure requires no stabilization or activation steps, which enhances the cost effectiveness of the synthesized electrode materials.

Pillared Carbon Membranes Derived from Cardo Polymers.

Carbon molecular sieve membranes (CMSMs) were prepared by carbonizing the high free volume polyimide BTDA-BAF that is obtained from the reaction of benzophenone-3,3',4,4'-tetracarboxylic dianhydride (BTDA) and 9,9-bis(4-aminophenyl) fluorene (BAF). The bulky cardo groups prevented a tight packing and rotation of the chains that leads to high permeabilities of their CMSMs. The incorporation of metal-organic polyhedra 18 (MOP-18, a copper-based MOP) in the BTDA-BAF polymer before pyrolysis at 550 °C prevented the collapse of the pores and the aging of the CMSMs.

Two-Dimensional Hexagonal-Shaped Mesoporous Carbon Sheets for Supercapacitors.

Two-dimensional mesoporous hexagonal carbon sheets (MHCSs) have been prepared via a chemical vapor deposition method employing mesoporous Mg(OH) hexagonal sheets as the template and acetylene gas as the carbon precursor. MHCSs with porosity in the micropore-mesopore range have a high specific surface area of 1785 m·g. The hierarchical microporous-mesoporous pore structure enables rapid ion transport across the hexagonal carbon sheets, resulting in superior electrochemical performance.

Hybrid supercapacitors using electrodes from fibers comprising polymer blend-metal oxide composites with polymethacrylic acid as chelating agent.

Hybrid supercapacitors (SCs) made of carbon-metal oxide composites are devices which combine the advantages of electric double layer capacitors and pseudocapacitors viz high energy density, high power density and high cyclability. This is best achieved when the pseudocapacitive components are uniform in size and distribution on the conducting carbon support. Electrodes mats, fabricated from carbonized electrospun fibers generated from solutions of polyacrylonitrile (PAN) as the carbon source, cobalt (III) acetylacetonate as a metal oxide precursor, and polymethacrylic acid (PMAA) as a metal oxide precursor carrier were utilized in coin cell SCs.

Electrospun poly(acrylonitrile-co-itaconic acid) as a porous carbon precursor for high performance supercapacitor: study of the porosity induced by in situ porogen activity of itaconic acid.

An acrylonitrile based copolymer, poly(acrylonitrile-co-itaconic acid), P(AN-co-IA) was synthesized with different amounts of itaconic acid (IA) to study in situ porogen activity of IA to produce porous carbon nanofibers (CNFs) without any subsequent physical or chemical activation. The concept developed here avoids unnecessary and complex extra activation steps when fabricating CNFs which ultimately lead to lower char yields and uncontrollable pore sizes. The ability of COOH in P(AN-co-IA) to act as an in situ porogen by releasing CO during carbonization was verified by simultaneous thermogravimetric analysis-mass spectrometry compared to polyacrylonitrile (PAN).

Binder free carbon nanofiber electrodes derived from polyacrylonitrile-lignin blends for high performance supercapacitors.

Lignin was blended with polyacrylonitrile (PAN) in different ratios and fabricated into carbon nanofiber electrodes by electrospinning followed by thermal stabilization, carbonization and subsequent activation by CO of the carbonized mats. These carbon fiber electrodes exhibit high surface area, high mesoporosity, high graphitic content and high electrical conductivity. Activated carbon nanofiber mats derived from PAN:Lignin 70:30 blends display a surface area of 2370 m g with 0.

High performance supercapacitors using lignin based electrospun carbon nanofiber electrodes in ionic liquid electrolytes.

Flexible, free standing and binder-free electrodes were fabricated by electrospinning from a series of lignin: polyvinyl alcohol (PVA) polymer blends, followed by heat treatment. PVA has the dual function of facilitating the electrospinning of lignin and acting as a sacrificial polymer. Upon stabilization, carbonization and CO activation, carbon nanofibers (ACNF) derived from the lignin:PVA 80:20 blend displayed a high surface area of 2170 m g and a mesopore volume of 0.

Wrinkled Mesoporous Silica Supported Lanthanum Oxide as a Template for Porous Carbon.

Wrinkled mesoporous silica (WMS) has been shown to be a promising material for catalysis and drug delivery. The WMS possesses a unique wrinkled structure with conical shaped pores radiating from the center to the surface of each particle. Lanthanum oxide was supported on wrinkled mesoporous silica as a hard template for the synthesis of graphitic carbon.

Electrochemical energy storage performance of carbon nanofiber electrodes derived from 6FDA-durene.

Carbon nanofibers (CNFs) are promising electrode materials for electrochemical double layer capacitors due to their high porosity and electrical conductivity. CNFs were prepared by electrospinning and subsequent thermal treatment of a new precursor polymer, 6FDA-durene, without the addition of pore generating agents. The conversion of precursor nanofibers into CNFs was confirmed using Raman spectroscopy.

Carbonized Electrospun Nanofiber Sheets for Thermophones.

Thermoacoustic performance of thin freestanding sheets of carbonized poly(acrylonitrile) and polybenzimidazole nanofibers are studied as promising candidates for thermophones. We analyze thermodynamic properties of sheets using transport parameters of single nanofibers and their aligned and randomly electrospun thin film assemblies. The electrical and thermal conductivities, thermal diffusivity, heat capacity, and infrared blackbody radiation are investigated to extract the heat exchange coefficient and enhance the energy conversion efficiency.

Electrochemically active porous organic polymers based on corannulene.

For the first time, porous organic polymers (POPs) based on the smallest buckybowl, corannulene (BB-POPs) have been synthesized. Three POPs were synthesised via Sonogashira co-polymerization of 1,2,5,6-tetrabromocorannulene and alkyne linkers. BB-POP-3 exhibits the highest surface area (SA = 560 m g) and CO adsorption of 11.

Preparation of porous carbon nanofibers derived from PBI/PLLA for supercapacitor electrodes.

Porous carbon nanofibers were prepared by electrospinning blend solutions of polybenzimidazole/poly-L-lactic acid (PBI/PLLA) and carbonization. During thermal treatment, PLLA was decomposed, resulting in the creation of pores in the carbon nanofibers. From SEM images, it is shown that carbon nanofibers had diameters in the range of 100-200 nm.

Gas Separation Membranes Derived from High-Performance Immiscible Polymer Blends Compatibilized with Small Molecules.

An immiscible polymer blend comprised of high-performance copolyimide 6FDA-DAM:DABA(3:2) (6FDD) and polybenzimidazole (PBI) was compatibilized using 2-methylimidazole (2-MI), a commercially available small molecule. Membranes were fabricated from blends of 6FDD:PBI (50:50) with and without 2-MI for H2/CO2 separations. The membranes demonstrated a matrix-droplet type microstructure as evident with scanning electron microscopy (SEM) imaging where 6FDD is the dispersed phase and PBI is the continuous phase.

Instrument for gas permeation measurements at high pressure and high temperature.

An instrument was built for the permeation testing of flat polymer membranes under pressures up to 3.0 MPa and temperatures up to 300 °C. The high pressure, high temperature cell uses aluminum tape and a graphite gasket to minimize the leak from the high pressure side to the low pressure side, making possible the permeability measurements of slow diffusing gases such as N2.

Synthesis and characterization of a novel symmetrical sulfone-substituted polyphenylene vinylene (SO2EH-PPV) for applications in light emitting devices.

A novel symmetrical alkylsulfonyl-substituted poly(phenylenevinylene) derivative, poly [2,5-bis-(2'-ethylhexylsulfonyl)-1,4-phenylene)vinylene] (SO2EH-PPV), was synthesized via palladium-catalyzed Stille coupling, and its electronic and optical properties were investigated. The novel PPV derivative was characterized by NMR, UV-visible absorption, photoluminescence, gel permeation chromatography, infrared spectroscopy, and cyclic voltammetry (CV). The polymer with Mw of 27,800 and a polydispersity index of 2.

Vanadium oxide nanotube spherical clusters prepared on carbon fabrics for energy storage applications.

Vanadium oxide nanotubes have shown great promise as electrode materials for energy storage devices. In this study, we report the synthesis of V(2)O(5) nanotube (VNT) clusters, which form densely packed radial arrangements of VNTs on high-surface-area carbon fiber fabrics (CF). This was achieved by coating the CF with V(2)O(5) by pulsed laser deposition (PLD).

A novel dialkylthio benzo[1,2-b:4,5-b']dithiophene derivative for high open-circuit voltage in polymer solar cells.

A new dialkylthio benzo[1,2-b:4,5-b']dithiophene (S-BDT) was designed and synthesized and the polymer S-PBDT was prepared by a Stille coupling reaction. A high open-circuit voltage (V(oc)) of up to 0.99 V was achieved in polymer solar cells with PCBM.

Electrospinning of poly(alkoxyphenylenevinylene) and methanofullerene nanofiber blends.

Poly(p-phenylenevinylene) (PPV) derivatives have long been studied because of their attractive opto- and electroluminescent properties and have potential applications for devices such as light-emitting diodes and photovoltaics. The ability to induce alignment of these PPV derivatives may lead to the enhancement of charge mobility and their efficiency. In this study, uniform nanofibers of poly[2,5-(2'-ethylhexyloxy)]-1,4-phenylenevinylene (BEH-PPV) have been fabricated through the method of electrospinning, and an induced alignment of the polymer fibers was observed through photoluminescence data.

Harvesting waste thermal energy using a carbon-nanotube-based thermo-electrochemical cell.

Low efficiencies and costly electrode materials have limited harvesting of thermal energy as electrical energy using thermo-electrochemical cells (or "thermocells"). We demonstrate thermocells, in practical configurations (from coin cells to cells that can be wrapped around exhaust pipes), that harvest low-grade thermal energy using relatively inexpensive carbon multiwalled nanotube (MWNT) electrodes. These electrodes provide high electrochemically accessible surface areas and fast redox-mediated electron transfer, which significantly enhances thermocell current generation capacity and overall efficiency.

Fuel-powered artificial muscles.

Artificial muscles and electric motors found in autonomous robots and prosthetic limbs are typically battery-powered, which severely restricts the duration of their performance and can necessitate long inactivity during battery recharge. To help solve these problems, we demonstrated two types of artificial muscles that convert the chemical energy of high-energy-density fuels to mechanical energy. The first type stores electrical charge and uses changes in stored charge for mechanical actuation.

Electrospun MEH-PPV/SBA-15 composite nanofibers using a dual syringe method.

The process of electrospinning, which produces fibers in the nanometer to micron range under the influence of high voltages, has been widely studied to produce polymer and textile fibers. Mesoporous molecular sieve fibers have been produced in our lab, and this technique was extended to produce an interwoven mesh of polymer-molecular sieve composite fibers. The electroluminescent polymer MEH-PPV and molecular sieve SBA-15 were used to produce the composite fibers.

Heterogeneous electron-transfer kinetics for ruthenium and ferrocene redox moieties through alkanethiol monolayers on gold.

The standard heterogeneous electron-transfer rate constants between substrate gold electrodes and either ferrocene or pentaaminepyridine ruthenium redox couples attached to the electrode surface by various lengths of an alkanethiol bridge as a constituent of a mixed self-assembled monolayer were measured as a function of temperature. The ferrocene was either directly attached to the alkanethiol bridge or attached through an ester (CO(2)) linkage. For long bridge lengths (containing more than 11 methylene groups) the rate constants were measured using either chronoamperometry or cyclic voltammetry; for the shorter bridges, the indirect laser induced temperature jump technique was employed to measure the rate constants.