SAXSess made in Austria: Anton Paar GmbH Equips US University for Zeolite Study

bridges vol. 10, June 2006 / Noteworthy Information

In a recent collaboration with the University of Minnesota (Minneapolis), Anton Paar's state-of-the-art equipment enabled a team of chemists, engineers, and mathematicians to uncover new details of a decades-old mystery: the question of how certain zeolites form. The small crystals have been used in purifiers, filters, and other devices for a long time, but their creation and refinement are to a large extent a matter of sophisticated trial and error. Anton Paar GmbH provided the loan instrument - a small-angle X-ray scattering system named SAXSess - and also supplied the data evaluation software for the investigation of these small particles.

 

{access view=guest}Access to the full article is free, but requires you to register. Registration is simple and quick - all we need is your name and a valid e-mail address. We appreciate your interest in bridges.{/access} {access view=!guest}Anton Paar GmbH, a Graz-based company producing high-quality measuring and analysis instruments for research and industry, was established in 1922. Today it employs more than 650 people in nine locations and is contract manufacturer for companies all over the world. Continuous innovation and cooperation with universities and external research institutes is a key factor in the company's success.

Schnablegger_Heimo_caption Why is the formation process of zeolites a particularly tough question? Heimo Schnablegger, a former senior scientist at the Max Planck Institute for Colloids and Interfaces and now product manager for SAXSess at Anton Paar GmbH, explains: "Small particles are hard to observe. Particularly their formation in liquids is still a mostly speculated-about topic. The reason for this is that particles pop into existence at unpredictable times and at more or less random places. Theoretical attempts to explain nucleation-and-growth processes are numerous but need experimental validation. Reliable investigation techniques are vital for these endeavors. The required equipment is either homemade or provided by companies who have the expertise to comply with the required specifications."

Basically, two techniques are commonly favored for the investigation of these small particles: Electron Microscopy and Small-Angle X-Ray Scattering (SAXS).

"Electron Microscopy," says Schnablegger, "gives clear pictures of the particles in a small selected sample area. Their shape and size can be viewed directly and in high resolution, provided that one looks at the right spot at the right time. This difficulty is overcome by freezing all motion inside the sample, so that a particular time snapshot can be investigated at leisure and in detail."

Small-Angle X-ray Scattering is the other method. Schnablegger explains the advantages of SAXS: "The whole sample volume - and not just a small part therefrom - can be investigated at the same time, so that good average values are obtained at once. It confirms the results of microscopy and adds statistical significance to it. The samples are usually investigated in vitro, i.e., without sample freezing, drying, or other preparation techniques that have the potential to destroy the structures before you can even look at them."

The cooperation between the University of Minnesota and Anton Paar GmbH applied the mechanistic principles of nanoparticle evolution to zeolite crystals, achieving a new level of understanding: Small particles of silica were observed to form in quite a uniform and narrow size range. These primary particles then self-assembled into an ordered (crystalline) superstructure, the precursors of zeolites. Get more information at
http://www.nsf.gov/news/news_summ.jsp?cntn_id=106892&org=NSF&from=news.

The application of SAXess is not limited to the investigation of silica nanoparticles. It has already been used to characterize proteins, viruses, paints, emulsions, micelles, vesicles, cellulose, and many types of synthetic polymers. Application notes on many of these topics can be requested from Anton Paar's homepage http://www.anton-paar.com.


For further information, please contact
Heimo Schnablegger
heimo.schnablegger(at)anton-paar.com

Related Link
Tracy M. Davis, Timothy O. Drews, Harikrishnan Ramanan ,2, Chuan He, Jingshan Dong, Heimo Schnablegger, Markos A. Katsoulakis , Efrosini Kokkoli, Alon V. McCormick, R. Lee Penn and Michael Tsapatsis "Mechanistic Principles of Nanoparticle Evolution to Zeolite Crystals," Nature Materials 5 (April 2006): 400-408. http://www.cems.umn.edu/research/kokkoli/pubs/Nat%20Mat.pdf

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