Advanced Powder Technology, Vol.27, No.4, 1325-1336, 2016
Application of particle sedimentation analysis in sterically-stabilized TiO2 particles stability assessment
Particle sedimentation analysis is an important characterization technique for making reliable stability assessment of particles in suspensions. In this work, new analytical model was derived similar to Kynch's continuity equation where negligible compression effect and constant solid volume concentration phi(s) are assumed at the compression phase. However, this new model differs as it includes new expressions for forces due to inertia and accelerated fluid eddies. The new model was also employed in analysing dynamics of particles during sedimentation thereby making it useful to assess particle stability in suspensions as well as predict particle sedimentation profiles if variation of phi(s) with time can be accurately measured. Stability of monodisperse spherically shaped TiO2 particles synthesized by the well-accepted sol-gel process and sterically stabilized separately by two different commercial surfactants, Brij30 and Brij76, were assessed via an instrument called Turbiscan and it operates based on principle of multiple light scattering (MLS) technique. The instrument measures variations in particle size and position as function of time and records as backscattered (BS) or transmitted (T) light intensity which can then be converted to phi(s) expressed in terms of attenuation time and height. This makes the instrument applicable in validating the newly derived analytical model. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.