Jump to main content
Jump to site search

Issue 6, 2018
Previous Article Next Article

Activity-induced instability of phonons in 1D microfluidic crystals

Author affiliations

Abstract

One-dimensional crystals of passively-driven particles in microfluidic channels exhibit collective vibrational modes reminiscent of acoustic ‘phonons’. These phonons are induced by the long-range hydrodynamic interactions among the particles and are neutrally stable at the linear level. Here, we analyze the effect of particle activity – self-propulsion – on the emergence and stability of these phonons. We show that the direction of wave propagation in active crystals is sensitive to the intensity of the background flow. We also show that activity couples, at the linear level, transverse waves to the particles' rotational motion, inducing a new mode of instability that persists in the limit of large background flow, or, equivalently, vanishingly small activity. We then report a new phenomenon of phonons switching back and forth between two adjacent crystals in both passively-driven and active systems, similar in nature to the wave switching observed in quantum mechanics, optical communication, and density stratified fluids. These findings could have implications for the design of commercial microfluidic systems and the self-assembly of passive and active micro-particles into one-dimensional structures.

Graphical abstract: Activity-induced instability of phonons in 1D microfluidic crystals

Back to tab navigation

Supplementary files

Publication details

The article was received on 05 Jul 2017, accepted on 28 Dec 2017 and first published on 02 Jan 2018


Article type: Paper
DOI: 10.1039/C7SM01335C
Citation: Soft Matter, 2018,14, 945-950
  •   Request permissions

    Activity-induced instability of phonons in 1D microfluidic crystals

    A. C. H. Tsang, M. J. Shelley and E. Kanso, Soft Matter, 2018, 14, 945
    DOI: 10.1039/C7SM01335C

Search articles by author

Spotlight

Advertisements