Size and Shape Characterization of Ensembles of Crystalline Powders
5th October 2023 at 3pm (UK time)
Particle size and
shape distribution (PSSD) significantly impacts the macroscopic properties of
powders, influencing attributes such as flowability, filterability, and
compressibility. Particularly noteworthy are needle-like and plate-like
particles, prevalent in pharmaceutical and agrochemical industries, presenting
considerable manufacturing hurdles. Accurately characterizing PSSDs of particle
ensembles is crucial for effective process design, modeling, and control to
address specific manufacturing challenges arising from these unfavorable
have been proposed and deployed at laboratory and pilot scales to characterize
the PS(S)Ds. State-of-the-art methods, like laser diffraction, focused beam
reflectance measurement, and Coulter counter, assume spherical shapes and
describe particles using a single size descriptor - the sphere's diameter.
While this assumption may suffice for quality control objectives, it can
misguide practitioners when dealing with products exhibiting needle- or
plate-like morphologies due to their asymmetric shapes. Emerging alternatives
like Malvern's Morphologi and BlazeMetrics probes are enhancing traditional
techniques by enabling shape resolution of particle ensembles. However, these
devices often consolidate shape features into a single size descriptor, and
obtaining high time-resolution data can be challenging. Moreover, even when
shape features are not lumped, these devices typically offer a maximum of two
size descriptors—length and width—adding to the challenge of characterizing
Over the last
decade, we have addressed these challenges to obtain high time-resolution data
and characterizing particles using one, two, or three size descriptors. To this
end, we have developed two innovative techniques: an online stereoscopic
imaging device, the DISCO [1,2], and an offline combined imaging and confocal
microscopy device, the Petroscope . These techniques accurately resolve the
size and shape of particle ensembles, enabling a deeper understanding of their
characteristics. In this talk, we will delve into the multiple facets of our
approach, highlighting how we overcame these challenges, comparing our
techniques with industry standards, and demonstrating how the insights gained
through precise process monitoring have enhanced the design and control of
processes relevant to industry .
 Rajagopalan, A.
K.; Schneeberger, J.; Salvatori, F.; Bötschi, S.; Ochsenbein, D. R.; Oswald, M.
R.; Pollefeys, M.; Mazzotti, M. A Comprehensive Shape Analysis Pipeline for
Stereoscopic Measurements of Particulate Populations in Suspension. Powder
Technol. 2017, 321, 479–493.
 Binel, P.;
Jain, A.; Jaeggi, A.; Biri, D.; Rajagopalan, A. K.; DeMello, A. J.; Mazzotti,
M. Online 3D Characterization of Micrometer-Sized Cuboidal Particles in
Suspension. Small Methods 2023, 7 (1), 2201018.
P.; Vetter, T.; Cruz-Cabeza, A.; Rajagopalan, A. K. Combined Imaging and
Chromatic Confocal Microscopy Technique to Characterize Size and Shape of
Ensembles of Cuboidal Particles. ChemRxiv. 2023; https://doi.org/10.26434/chemrxiv-2023-nw1hs
 Bötschi, S.;
Rajagopalan, A. K.; Rombaut, I.; Morari, M.; Mazzotti, M. From Needle-like toward
Equant Particles: A Controlled Crystal Shape Engineering Pathway. Comput. Chem.
Eng. 2019, 131, 106581.
This webinar will be presented by Ashwin Kumar Rajagopalan, Lecturer in Chemical Engineering, University
If you wish to register please contact firstname.lastname@example.org