Using Janus Particles to Control Mixing and Segregation of Adhesive Particle Systems

Abstract

Processing of fine powders is a relevant operation in many industries, from pharmaceuticals to material synthesis. As the size of the particles decreases, adhesive forces become important and can have a nontrivial, but difficult to predict, impact on the mixing/segregation tendency of the material. The aim of this work is to control the final asymptotic state of adhesive systems through the addition of "helper" particles that can either promote mixing or segregation. These amphiphilic "helper" particlessalso called Janus particlessact as bridges between particles, alternatively promoting mixing in a system that would otherwise segregate (surfactant particles) or separating a specific kind of particle from a mixture (extractant particles). Phasespace diagrams of the expected behavior are analytically identified by comparing the interaction forces in the system: the strengths of those that promote mixing are compared with the ones that enhance segregation (including those interactions bridged by Janus particles), and the final state of the system is determined by the interactions that predominate. The predictions are then tested against results obtained by two-dimensional discrete element method (DEM) simulations of the system including Janus particles, which are further compared to both the binary adhesive system and the free-flowing case.

Passive rate‐based separation in collisional flows

“…Here we employ this method to model separation mechanisms for both single and multiple particle systems as a function of specific design parameters. This simulation technique has been successfully used in the study of mixing/segregation rates and patterns, discharge rates from hoppers, and free‐surface segregation . In all cases, the results display good agreement with experimental observations.…”

Particle Mixing Study in Rotating Wavy Wall Tumblers by Discrete Element Method Simulation

“…For the rich scientific essences and wide engineering applications, many scientists and engineers have been interested in the particle mixing and segregation phenomena in various types of mixers for several decades. Great improvements on the fundamentals and underlying mechanisms of the mixing and segregation of granular particles have been achieved. − …”

One‐Step Approach for the Preparation of Organic‐Inorganic Janus‐Like Particles by Alkalization of Polystyrene‐block‐Poly(2‐vinylpyridine)/FeCl3Complex Micelles

“…Janus particles having two different materials on opposite faces can differ in either their chemical functionalities or their geometric structures 1. Recently, Janus particles have attracted considerable attention because of their huge potential applications in numerous fields, for example as medical carriers,2 optical probes,3, 4 and interface‐stabilizing agents,5–8 in electronic or magnetic displays,9, 10 and as building blocks to prepare advanced, ordered structures 11, 12. Much work has been done to create Janus particles, including the photopolymerization of precursors in microfluidic channels,10, 13–16 layer‐by‐layer assembly,17 the self‐organized precipitation method,18, 19 the Pickering emulsion‐based method,20–23 controlled phase separation,24–27 and so on.…”