The mesoscopic collective behavior of thermophoretic active particle suspension under spatial-temporal modulated excitation field

Chong-Wai Io^1*, Yu-Xuan Shen¹

¹Department of Physics, National Chung-Cheng University, Minhsiung, Taiwan

* Presenter:Chong-Wai Io, email:phycwio@ccu.edu.tw

The suspension of self-propelling particle with controllable propelling strength could be one the simplest system to study non-equilibrium physics. Many previous studies show that, even in homogeneous environment, as increasing the self-propelling strength, such system exhibits a transition from equilibrium Brownian motion, to slightly non-equilibrium state with super-diffusion and then to far from equilibrium heterogeneous state with the coexistence of self-jamming cluster and fast propelling particle, so called motility-induced-phase-separation (MIPS). In general, it is interesting to extend to heterogeneous background. Although there are some studies addressed the behavior in static patterned environment, the spatial-temporal modulated environment is rarely been discussed, especially for experimental approach. In this work, by using a Digital Light Processing (DLP) chip, the spatial-temporal modulated laser pattern is generated to trigger the thermophoretic force of metal capped silica Janus particle. Their mesoscopic behavior in repose to difference traveling laser patterns and propagating speed will be reported.

Keywords: Active particle, Mesoscopic dynamics, Heterogeneous motion