Analytik, leading suppliers of innovative
analytical instrumentation, talk about the particle characterisation work
performed by Professor Steve Armes and his team in the Department of Chemistry
at the University of Sheffield.
Among the research interests of Professor Steve Armes is the synthesis and
characterisation of colloidal systems. His group has used disc centrifuge
photo-sedimentometry to size a wide range of latexes, sols and colloidal
nanocomposite particles over the last fifteen years. One of the tools used is
the high resolution 24,000 rpm disc centrifuge from CPS. This has delivered
reliable results with a wide range of latexes and nanocomposite particles. This
new instrument has a maximum centrifugation rate of 24,000 rpm, which is
substantially faster than the older Brookhaven disc centrifuge (15,000 rpm).
This means that much smaller particles can now be sized with good accuracy and
reproducibility.
The CPS disc centrifuge has proved to be particularly useful for sizing a
family of new poly(2-hydropropyl methacrylate) latexes prepared by aqueous
dispersion polymerisation (see A. M. Ali et al., Soft Matter, 2007, 2,
1003-1013). Since poly(2-hydroxypropyl methacrylate) is soluble in alcohol,
these particular latexes become swollen in methanol/water mixtures, which is
the normal spin fluid used for the Brookhaven instrument. This means that the
solid-state particle density determined by helium pycnometry is no longer
applicable, which invalidates the particle size measurement. In contrast, the
wholly aqueous spin fluid used in the CPS disc centrifuge prevents latex
swelling and allows meaningful particle size analyses to be performed. Other
advantages offered by the CPS disc centrifuge include its Windows software and
straightforward mode of operation which is well suited to sizing the many
different samples encountered within a typical laboratory day. This is
additionally useful to the Armes research group as they also offer a particle
size analysis service to industrial companies.
Discussing his use of the CPS, Professor Armes said, "We have shown that
the CPS disc centrifuge offers a very convenient means of verifying whether
silica redistribution occurs when polymer-silica nanocomposite particles are
challenged with excess latex. Such redistribution is accompanied by incipient
flocculation, which is readily detected if the challenging latex is chosen to
have a different size to the original nanocomposite particles. Although we have
also characterised silica redistribution using small-angle x-ray scattering,
electron microscopy and x-ray photoelectron spectroscopy, we find that the CPS
disc centrifuge is the easiest and most convenient technique for simply
establishing whether this phenomenon has occurred or not. The CPS instrument
has proved to be an indispensable characterisation tool in our research
programme and it should provide us with robust, reliable particle sizing
capability for many years to come."
To learn more about high-resolution particle size characterisation using the
CPS Disc Centrifuge, please visit
www.analytik.co.uk
Subscribe to any of our newsletters for the latest on new laboratory products, industry news, case studies and much more!
Request your free copies HERE
Popular this Month
Top 10 most popular articles this month
Today's Picks
Looking for a Supplier?
Search by company or by product
Please note Lab Bulletin does not sell, supply any of the products featured on this website. If you have an enquiry, please use the contact form below the article or company profile and we will send your request to the supplier so that they can contact you directly.
Lab Bulletin is published by newleaf marketing communications ltd.