(421j) Dynamic Self-Assembly in Anisotropic Colloidal Systems for Emergent and Synchronized Oscillation

Recent advances in electronic materials and colloidal science have led to the development of colloidal electronics. The colloidal electronic particles, comprised of polymers and low dimensional materials, integrate simultaneously the modularity of state-of-the-art electronics and the characteristic mobility of the colloidal particles in a dispersed phase. These mobile colloidal particles can have multiple functionalities including energy harvesting, chemical species sensing, and memory updating. While the fabrication of these artificial cell-sized systems represents a significant step forward, real biological cells exhibit complex and emergent behaviors in a synchronized and controlled oscillatory manner.

To realize the complex functions exhibited in natural systems, programmed dynamic self-assembly is explored in symmetry-broken colloidal electronic cells to achieve synchronized oscillations found previously only in their biological counterparts. Recently, we have reported on the development of Pt-patched microdiscs that can generate autonomous oscillatory beating behavior at the air-hydrogen peroxide interface. These Janus particles, which are fueled by the well-studied platinum-based catalytic reaction, exhibit a 4-step beating cycle that consists of (1) mutual approach, (2) oxygen bubble contact, (3) bubble merger, and (4) bubble rupture.

Despite the observed beating phenomena, the underlying kinetics require further analysis and elucidation both experimentally and in silico. In this study, we examine the physical parameters that affect the oscillatory behavior of the beating particle system and compare experimental observations with simulation models. Understanding the effects of these parameters will enable the design and engineering of Janus microparticles with more complex oscillatory beating behavior with improved frequency tunability and programmability.