Exploitation of inline photon density wave spectroscopy for titania particle syntheses

In this work, inline (or in-situ) monitoring of titania particle formation with photon density wave spectroscopy is shown to provide helpful information for process optimization for higher particle yields. Titania particles have been synthesized by the controlled hydrolysis of tetraethyl orthotitanate. Without calibration or dilution, photon density wave spectroscopy provides access to dispersions' reduced scattering coefficient μ_s'. Hence, information can be obtained inline about processes that are otherwise challenging for established particle characterization methods. Photon density wave spectroscopy results suggest that the titania particles disintegrate over time after their formation. Consistent with that hypothesis, a decreasing particle yield with reaction time has been observed. The disintegration can be hindered by adding a sufficient amount of hexadecylamine, such that the particle yield after 24 h can be increased by 44% for the given syntheses.