Visualization of Noncovalent Interaction between Aliphatic Dendrimers and Chemically Reduced Graphene Oxide

Chemically reduced graphene oxide (rGO) decorated with aliphatic dendrimers having gold nanoparticles either in their endo- or exo-positions was firstly formulated through fully noncovalent functionalization approaches. Noncovalent binding of aliphatic denchimers specifically on rGO rather than on graphene oxide (GO) could be clearly visualized in transmission electron microscopy analysis.close

Rapid separation of bacteriorhodopsin using a laminar-flow extraction system in a microfluidic device

A protein separation technology using the microfluidic device was developed for the more rapid and effective analysis of target protein. This microfluidic separation system was carried out using the aqueous two-phase system (ATPS) and the ionic liquid two-phase system (ILTPS) for purification method of the protein sample, and the three-flow desalting system was used for the removal of salts from the sucrose-rich sample. Partitioning of the protein sample was observed in ATPS or ILTPS with the various pHs. The microdialysis system was applied to remove small molecules, such as sucrose and salts in the microfluidic channel with the different flow rates of buffer phase. A complex purification method, which combines microdialysis and ATPS or ILTPS, was carried out for the effective purification of bacteriorhodopsin (BR) from the purple membrane of Halobacterium salinarium, which was then analyzed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis and matrix-assisted laser desorption∕ionization time-of-flight. Furthermore, we were able to make a stable three-phase flow controlling the flow rate in the microfluidic channel. Our complex purification methods were successful in purifying and recovering the BR to its required value

Graphene phosphonic acid as an efficient flame retardant

We report the preparation of graphene phosphonic acid (GPA) via a simple and versatile method and its use as an efficient flame retardant. In order to covalently attach phosphorus to the edges of graphene nanoplatelets, graphite was ball-milled with red phosphorus. The cleavage of graphitic C-C bonds during mechanochemical ball-milling generates reactive carbon species, which react with phosphorus in a sealed ball-mill crusher to form graphene phosphorus. Subsequent opening of the crusher in air moisture leads to violent oxidation of graphene phosphorus into GPA (highest oxidation state). The GPA is readily dispersible in many polar solvents, including neutral water, allowing for solution (spray) coating for high-performance, nontoxic flame-retardant applications.close0

Water-Based Thixotropic Polymer Gel Electrolyte for Dye-Sensitized Solar Cells

For the practical application of dye-sensitized solar cells (DSSCs), it is important to replace the conventional organic solvents based electrolyte with environmentally friendly and stable ones, due to the toxicity and leakage problems. Here we report a noble water-based thixotropic polymer gel electrolyte containing xanthan gum, which satisfies both the environmentally friendliness and stability against leakage and water intrusion. For application in DSSCs, it was possible to infiltrate the prepared electrolyte into the mesoporous TiO2 electrode at the fluidic state, resulting in sufficient penetration. As a result, this electrolyte exhibited similar conversion efficiency (4.78% at 100 mW cm(-2)) and an enhanced long-term stability compared to a water-based liquid electrolyte. The effects of water on the photovoltaic properties were examined elaborately from the cyclic voltammetry curves and impedance spectra. Despite the positive shift in the conduction band potential of the TiO2 electrode, the open-circuit voltage was enhanced by addition of water in the electrolyte due to the greater positive shift in the l(-)/l(3)(-) redox potential. However, due to the dye desorption and decreased diffusion coefficient caused by the water content, the short-circuit photocurrent density was reduced. These results will provide great insight into the development of efficient and stable water-based electrolytes