Fiber-optical particle sizing by photon density wave spectroscopy

Abstract

Photon Density Wave (PDW) spectroscopy is introduced as a fiber-optical technique for the in-line and dilution-free determination of the droplet or particle size in highly turbid emulsions and suspensions, respectively. Here, focus is laid on the monitoring of the Phase Inversion Temperature (PIT) emulsification process. The different stages like the inversion from an oil-in-water to a water-in-oil macroemulsion and finally to an oil-in-water nanoemulsion are observed and the droplet size is determined with high temporal resolution. This process shows the capability of PDW spectroscopy to determine particle or droplet sizes over a wide range from the nanometer to micrometer scale.