Nanostructures for enzyme stabilization

Nanostructures in Water-in-CO2 Microemulsions Stabilized by Double-Chain Fluorocarbon Solubilizers

Abstract Image† Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan

‡ Department of Chemistry, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjong Malim, Perak 35900, Malaysia

§ School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom

ISIS-CCLRC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, United Kingdom

Langmuir, 2013, 29 (25), pp 7618–7628

DOI: 10.1021/la400376g

Abstract

High-pressure small-angle neutron scattering (HP-SANS) studies were conducted to investigate nanostructures and interfacial properties of water-in-supercritical CO2 (W/CO2) microemulsions with double-fluorocarbon-tail anionic surfactants, having different fluorocarbon chain lengths and linking groups (glutarate or succinate). At constant pressure and temperature, the microemulsion aqueous cores were found to swell with an increase in water-to-surfactant ratio, 0, until their solubilizing capacities were reached. Surfactants with fluorocarbon chain lengths of = 4, 6, and 8 formed spherical reversed micelles in supercritical CO2 even at 0 over the solubilizing powers as determined by phase behavior studies, suggesting formation of Winsor-IV W/CO2 microemulsions and then Winsor-II W/CO2 microemulsions. On the other hand, a short C2 chain fluorocarbon surfactant analogue displayed a transition from Winsor-IV microemulsions to lamellar liquid crystals at 0 = 25. Critical packing parameters and aggregation numbers were calculated by using area per headgroup, shell thickness, the core/shell radii determined from SANS data analysis: these parameters were used to help understand differences in aggregation behavior and solubilizing power in CO2. Increasing the microemulsion water loading led the critical packing parameter to decrease to 1.3 and the aggregation number to increase to >90. Although these parameters were comparable between glutarate and succinate surfactants with the same fluorocarbon chain, decreasing the fluorocarbon chain length reduced the critical packing parameter. At the same time, reducing chain length to 2 reduced negative interfacial curvature, favoring planar structures, as demonstrated by generation of lamellar liquid crystal phases.

Catalyst Could Jump-Start E-Cars

by 56andfixed


June 4, 2013
Los Alamos National Laboratory scientists have designed a new type of nanostructured-carbon-based catalyst that could pave the way for reliable, economical next-generation batteries and alkaline fuel cells, providing for practical use of wind- and solar-powered electricity, as well as enhanced hybrid electric vehicles.
In a paper appearing recently in Nature Communications, Los Alamos researchers Hoon T. Chung, Piotr Zelenay and Jong H. Won, the latter now at the Korea Basic Science Institute, describe a new type of nitrogen-doped carbon-nanotube catalyst

Depleted Uranium and our troops and all those

by living-in-the-ME


Oct. 2006: President George W. Bush signed the Department of Defense Authorization legislation. The House amendment was authored and introduced by Rep. Jim McDermott (D-Wa.) ordering a comprehensive study - with a report due in one year - on possible adverse health effects on U.S. soldiers from the U.S. military's use of DU - Depleted Uranium. The Senate companion bill was backed by Joe Lieberman of Conn., a democrat at the time. (McDermott's Web site: )
Feb. 6, 2007: The New York newspaper, The Post Chronicle, reported that U

Nanotubes Increase Solar PV Conductivity 100 Million-Fold  — Sourceable
Carbon-based nanostructures are already being used as materials in solar cells with increasing frequency, yet their ability to enhance electrical performance has thus far been hampered by limited ability to assemble orderly networks using the materials.

Wiley-Scrivener Biomimetics: Advancing Nanobiomaterials and Tissue Engineering
Book (Wiley-Scrivener)
Springer Biologically Responsive Biomaterials for Tissue Engineering (Springer Series in Biomaterials Science and Engineering)
Book (Springer)
Related Posts