The 2022 “Alkiviades Ch. Payatakes” Distinguished Lecture was delivered by Professor Marios Ioannidis, Department of Chemical Engineering, University of Waterloo. The lecture was entitled “Nanoparticles as Surfactants: Lessons from a Model System” and was held on Thursday, 15 December 2022, at 13:00, at the ICEHT Conference Center. 

Abstract

Like surfactants, small solid particles can adsorb at gas−liquid and liquid−liquid interfaces, reducing the surface or interfacial tension. Thus, like surfactants, colloidal particles can act as emulsifiers, stabilizing so-called Pickering emulsions and foams. Attachment and self-assembly of nanoparticles at the liquid-liquid or gas-liquid interface is, in fact, relevant to great many processes of scientific and technological significance.  These include the fabrication of advanced materials with a variety of functionalities (e.g., sensing, drug delivery, catalysis, separation, etc.), the transport and fate of nano-plastics in the environment, the in situ remediation of subsurface contamination, and so on.  Important differences exist, however, between the behavior of molecular surfactants and nanoparticles.  Here, a model colloidal system of hydrophobic, charge-stabilized ethyl cellulose nanoparticles illustrates these differences and serves as a testbed for theoretical predictions and a springboard for new developments.

Short CV

Marios Ioannidis is a Professor of Chemical Engineering at the University of Waterloo, Canada, where he currently serves as Chair of the Department of Chemical Engineering.  Marios first studied chemical engineering at the University of Patras, obtaining the Diploma in Chemical Engineering in 1988, and continued his studies at the University of Waterloo, obtaining a PhD degree in Chemical Engineering in 1993.  Marios and his students research fundamental aspects of multiphase flow and transport of solutes and nanoparticles in porous materials of different kinds (fibrous or granular, man-made or natural, etc.). The goal of their research is to enable engineering applications ranging from subsurface remediation and petroleum production to environmental sampling, fuel cell performance optimization and oil spill response. Professor Ioannidis has held numerous administrative positions within the University of Waterloo, including as Director of the Nanotechnology Engineering Program, and is a Fellow of Engineers Canada.