Janus Particles & Soft Matter


Individual particles with interesting properties can assemble to make new types of soft matter.

Slippery Particles

When liquid flows over a surface, the liquid layer next to the surface is usually considered stationary. In recent times, very small violations of this “no-slip boundary condition” have been measured for water on hydrophobic surfaces. The motion of a particle on flow should be affected if it has a slippery surface [1]. We are carrying out experiments to test this theory, and using molecular dynamics simulations [2] to understand the implications for asymmetric Janus particles.

Collective Dynamics

We can also study the dynamics of two or more interacting Janus spheres. We are especially interested in how these particles come together to form interesting out-of-equilibrium phases. In experimental work, we are trying to observe Janus colloids as they are brought together in a microfluidic system. Using molecular dynamics simulations, we can study these interactions and how they lead to clustering and dispersion under different conditions. In theoretical work, we hope to model the phases and patterns which emerge in many-particle systems.


[1] Willmott, G. R. Slip-Induced Dynamics of Patterned and Janus-like Spheres in Laminar Flows. Phys. Rev. E 79, 066309 (2009).

[2] Safaei, S., Archereau, A. Y. M., Hendy, S. C. & Willmott, G. R. Molecular dynamics simulations of Janus nanoparticles in a fluid flow. Soft Matter 15, 6742-6752 (2019).


Location: Building 303, 38 Princes Street, Auckland, New Zealand
Phone: +64 9 373 7599 ext 89998
Email: g.willmott[at]auckland.ac.nz

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