Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Embedded Rods

11.10.2010
Chitin-silicon dioxide nanocomposite made by self-organization and sol-gel chemistry

Self-organization processes involving chemical building blocks are the basis for many biological processes and are increasingly of interest in the field of materials synthesis, for example in the production of highly ordered nanocomposites or high-porosity materials with special properties.

In the journal Angewandte Chemie, Bruno Alonso and Emmanuel Belamie from the Charles Gerhardt Institute in Montpellier (France) have introduced a novel, highly versatile approach to the large-scale synthesis of a new family of bioorganic–inorganic nanocomposites—with a previously unattainable degree of control over the composition and structure of the materials produced.

Nanocomposites are solid materials made of different substances, one of which is in the form of nanoparticles. The properties of the composites differ significantly from those of the pure individual components. Nanocomposites can also serve as “molds” for the production of porous substances. These have potential application in the areas of gas storage, catalysis, or materials separation.

For their synthesis, the researchers chose to use a sol–gel process, a popular technique for the production of inorganic network structures. In the first step they needed to generate a sol: a suspension of finely divided nanoscopic particles in a solvent. Their challenge was to obtain co-suspension of the two different components, silicon dioxide precursors (siloxane oligomers) and chitin nanorods from shrimp shells (a renewable resource). However, these two components require different conditions to remain in stable suspensions without uncontrolled precipitation. The researchers produced an alcohol suspension by slowly replacing water with ethanol. Through slow removal of the solvent, a gel formed. Gels are gelatinous substances; they contain solid but loose, cross-linked, three-dimensional polymer structures.

The sol can be “poured” into a desired mold and dried or it can be spray-dried into spherical particles. This process results in a nanocomposite made of chitin rods that are fully embedded in a silicon dioxide matrix. The mechanism by which this occurs is based on a self-organized aggregation of the chitin molecules and weak attractive forces between chitin and siloxane oligomers.

The stability of the alcohol suspensions opens up a wide range of possibilities for the production of materials with controllable volume ratios, spatial arrangements, and morphologies. If a magnetic field is applied during preparation of the material, the chitin rods line up in parallel. If the nanocomposite is heated, the chitin rods can be burned off to leave behind cavities. This forms a highly porous material with interesting properties.

Author: Emmanuel Belamie, Institut Charles Gerhardt, Montpellier (France), mailto:emmanuel.belamie@enscm.fr

Title: Chitin–Silica Nanocomposites by Self-Assembly

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201002104

Emmanuel Belamie | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>