Dynamics and interactions of particles in a thermophoretic trap

TL;DR

This study explores the behavior and interactions of non-spherical particles levitated by thermophoresis in a vacuum, revealing unique spinning motions and inter-particle forces, providing insights into particle dynamics in microgravity-like conditions.

Contribution

It introduces observations of non-spherical particle dynamics and interactions in a thermophoretic trap, highlighting new qualitative features not seen with spherical particles.

Findings

Non-spherical particles spin around their axes.

Particles exhibit both attractive and repulsive interactions.

Levitated particles demonstrate complex motion patterns.

Abstract

We investigate dynamics and interactions of particles levitated and trapped by the thermophoretic force in a vacuum cell. Our analysis is based on footage taken by orthogonal cameras that are able to capture the three dimensional trajectories of the particles. In contrast to spherical particles, which remain stationary at the center of the cell, here we report new qualitative features of the motion of particles with non-spherical geometry. Singly levitated particles exhibit steady spinning around their body axis and rotation around the symmetry axis of the cell. When two levitated particles approach each other, repulsive or attractive interactions between the particles are observed. Our levitation system offers a wonderful platform to study interaction between particles in a microgravity environment.