Heterogeneous Time Dependent Static Light Scattering (HTDSLS)

Principle: Use flow to create countable scattering peaks from colloidal particles, while simultaneously monitoring the background scattering due to co-existing polymers

• Determine large particle densities amid polymer chains; e.g. spherulites, microgels, bacteria, crystallites, etc.
  
  
• Follow evolution of large particles; e.g. in biotechnology reactors where bacteria/polymers co-exist. e.g. xanthan productions, degradation of polysaccharides, other fermentation reactions.
  
  
• Permits useful characterization of polymers in solutions which, up until now, would be considered far too contaminated with dust and other scatterers.

Applications of HTDSLS

1. Good data from a classically intractable case of high particulate contamination: a full Zimm plot determination of a polymer (PVP) coexisting with a colloid (2 mm latex spheres) (R. Schimanowski; R. Strelitzki; D. A. Mullin; W. F. Reed, Macromolecules 1999, 32, 7055-7063).

Left: Raw data for a mixture of PVP and 2 mm latex spheres at a concentration of 5120 particles/ml. Right: Zimm plot resulting from the data from left.

2. HTDLS on a Biological Test System: co-existing E. Coli and PVP polymers in solution (R. Schimanowski; R. Strelitzki; D. A. Mullin; W. F. Reed, Macromolecules 1999, 32, 7055-7063).

100 second wide swaths of raw data at different times for growing E. coli at 38°C for the 90° detector. The insets show the count rate F vs. time for these data and scattering recovered from the PVP.

Publications

R. Schimanowski; R. Strelitzki; D. A. Mullin; W. F. Reed, " Heterogeneous Time Dependent Light Scattering", Macromolecules 1999, 32, 7055-7063.