Date of Award


Degree Name

Master of Science in Engineering


Chemical and Paper Engineering

First Advisor

Dr. Kalyana C. Pingali

Second Advisor

Dr. Andrew Kline

Third Advisor

Dr. Raja Aravamuthan

Fourth Advisor

Dr. James Springstead


Triboelectrification, nanosmears, coating, powder flow, cohesion

Access Setting

Masters Thesis-Open Access


The main objective of the research project is to detect and quantify the rate and extent of nanosmearing of hydrophobic functional groups of additives on multiple pharmaceutical particles during high shear mixing of formulations due to electrostatics affecting critical blend properties on the bulk scale. We accomplished this task by systematically detecting the electrostatics during powder flow and its consequence on the nanosmearing distribution of additives during mixing. In the first stage, the electrostatic behavior of particles was correlated to the powder flow. Secondly, its relative influence on nanosmearing of additives during mixing was determined by developing a methodology to quantify (a) rate and (b) extent of nanosmearing. In the third stage, the distribution and % extent of hydrophobic additive affecting the critical blend properties were investigated. For the first time in the field of particle technology, Raman Spectroscopy was employed to develop an innovative method to quantify the presence and % extent of nanosmears of hydrophobic additive (magnesium stearate). The results indicated that electrostatic charges are generated due to particle interaction during powder flow. A direct correlation between charge accumulation and dissipation to the forces acting on the load cell measurements were found. Applied process shear increased the % nanosmeared area on multiple particle surfaces which improved the overall powder flow. A direct correlation between nanosmearing with applied process shear, cohesion and electrostatics was found.


Fifth Advisor: Dr. Brian Young