Paper Number
AD2 

Session
Rheology of Active Matter and Directed Systems

Title
Thermocapillary motion of a solid Janus microcylinder near a liquid-gas interface

Presentation Date and Time
October 12, 2022 (Wednesday) 1:50

Track / Room
Track 4 / Michigan AB

Authors (Click on name to view author profile)

  1. Arslanova, Alina (KU Leuven, Department of Chemical Engineering)
  2. Natale, Giovanniantonio (University of Calgary, Department of Chemical and Petroleum Engineering)
  3. Reddy, Naveen (Hasselt University, Institute for Materials Research)
  4. Fransaer, Jan (KU Leuven, Department of Materials Engineering)
  5. Clasen, Christian (KU Leuven, Department of Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Alina Arslanova1, Giovanniantonio Natale2, Naveen Reddy3, Jan Fransaer4 and Christian Clasen1
1Department of Chemical Engineering, KU Leuven, Leuven, Belgium; 2Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Canada; 3Institute for Materials Research, Hasselt University, Diepenbeek, Belgium; 4Department of Materials Engineering, KU Leuven, Leuven, Belgium

Speaker / Presenter 
Arslanova, Alina

Keywords
theoretical methods; active matter

Text of Abstract
The propulsion of active microparticles is a quickly growing research area with promising applications in sensing, manipulation of microscopic matter, or transporting active pharmaceutical ingredients to specific locations in the human body. A common mechanism of propulsion relies on a catalytic fuel decomposition by a Janus particle with asymmetric surface properties. However, low efficiency and high dependence on the fuel content significantly hinder the prospective applications of such active particles [1]. An alternative and mainly overlooked way of generating a particle motion is by exploiting its interactions with a liquid-fluid interface. In particular, when the temperature of a particle surface differs from the bulk, it can set itself into motion by a targeted induction of Marangoni stresses via an inhomogeneous temperature distribution along a nearby liquid-fluid interface causing a thermocapillary flow [2]. By deriving an exact analytical solution for the thermocapillary motion of a solid isotropically radiating cylinder near a liquid-gas interface, we showed that this mechanism provides an efficiency that is several orders of magnitude larger than those for (electro-)chemically propelled particles [3]. Moreover, expanding this study to Janus and patchy cylinders with a varying temperature distribution along the surface and an anisotropic radiation revealed rich dynamics of these systems with several modes of swimming, depending on the temperature anisotropy and the orientation of the Janus boundaries towards the surface. In this paper we show how thermally induced Marangoni stresses at liquid-liquid interfaces can provide an effective way to generate and modulate the microparticle’s propulsion, which is especially of interest for the regulation of adsorption of particles at the interface. References: [1] W. Wang, et al., JACS 135(28), 10557-10565 (2013) [2] A. Domínguez, et al., Physical Review Letters 116, 078301 (2016) [3] A. Arslanova, et al., Phys. Fluids 32(12), 127109 (2020)