Transition from Linear to Circular Motion in Active Spherical-Cap Colloids

Abstract

Nonspherical self-propelling colloidal particles offer many possibilities for creating a variety of active motions. In this work, we report on the transition from linear to circular motion of active spherical-cap particles near a substrate. Self-propulsion is induced by self-diffusiophoresis by catalytic decomposition of hydrogen peroxide (H2O2) on one side of the particle. Asymmetric distribution of reaction products combined with the asymmetric shape of the particle gives rise to two types of motions depending upon the relative orientation of the particle with respect to the underlying substrate. At a low concentration of H2O2, linear active motion is observed, whereas increasing the H2O2 concentration leads to persistent circular motion. However, the speed of self-propulsion is nearly independent of the size of the particle. The study demonstrates the use of nonspherical particles to create linear and circular motion by varying the fuel concentration.

Sorting and Extraction of Self-Propelled Chiral Particles by Polarized Wall Currents

“…The average period of the circular trajectory for a particle is hTi ¼ 1.33 s (see Supplemental Material, I [47]). This circular trajectory is similar to the trajectories obtained with asymmetric [48][49][50] or symmetric [51] particles and in simulations of selfpropelled particles with an added torque [16,[19][20][21]23]. Figure 1(b) shows a second trajectory for the same righthanded particle guided by the wall in a counterclockwise surface mode.…”

Investigating Time‐Dependent Active Motion of Janus Micromotors using Dynamic Light Scattering

“…Prior works similarly report decreases in τ R and its invariance with fuel concentration. [ 58–60 ] Notably, Dietrich et al. [ 59 ] reported τ R for PS‐Pt JMs was invariant of fuel concentration, but that the change in τ R upon fuel addition was dependent on the swimming environment.…”

Catalytically propelled 3D printed colloidal microswimmers

“…One such study showed that L-shaped particles exhibit circular trajectories. 22 More recent experiments on select anisotropic shapes or patches confirmed some of the predictions in 2D [23][24][25][26] and found unexpected motion patterns such as non-cylindrical helices 27 in 3D. Still, the current limitations in particle design prevent a systematic comparison with theory.…”