Title: Phase separation and state oscillation of active inertial particles

Abstract

Active matter systems are of great interest for their novel out-of-equilibrium collective behavior. Active Brownian particles (ABPs) are known to exhibit clustering and motility-induced phase separation, and there have been many studies revealing this rich behavior in the overdamped limit of Brownian motion, where inertial effects are insignificant. In this work, we simulate an Active Inertial Particle (AIP) model where we focus on the underdamped, rather than overdamped limit, to study the interplay between particle inertia and collective behavior, such as phase separation. We show that inertia reduces particle motility due to collisions and a longer time delay for particles to regain speed, thereby suppressing phase separation relative to that observed in the overdamped limit. Additionally, we observe interesting oscillatory behavior between a phase separated steady-state and a homogeneous fluid state that results from inertia-induced collective motion within active clusters due to momentum transfer. Such oscillatory behavior has been reported for ABP systems with particle shape anisotropy, where collective motion is mediated by particle shape anisotropy. Furthermore, we confirm that there is no single characteristic frequency for the oscillatory behavior. The power spectral density is a power law in the high frequency domain, with an exponent close to -2.5.

Authors:

Dai, Chengyu ^[1]; Bruss, Isaac R.  ^[1];

• Search DOE PAGES for author "Bruss, Isaac R."
• Search DOE PAGES for ORCID "0000-0002-7059-9552"

Glotzer, Sharon C.  ^[2]

• Search DOE PAGES for author "Glotzer, Sharon C."
• Search DOE PAGES for ORCID "0000-0002-7197-0085"

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+ Show Author Affiliations

1. Univ. of Michigan, Ann Arbor, MI (United States)
2. Univ. of Michigan, Ann Arbor, MI (United States); Univ. of Michigan, Ann Arbor, MI (United States). Biointerfaces Inst.

Publication Date:

Thu Feb 13 00:00:00 EST 2020

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Bio-Inspired Energy Science (CBES); Northwestern Univ., Evanston, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1767708

Alternate Identifier(s):

OSTI ID: 1602067

Grant/Contract Number:  

SC0000989

Resource Type:

Accepted Manuscript

Journal Name:

Soft Matter

Additional Journal Information:

Journal Volume: 16; Journal Issue: 11; Journal ID: ISSN 1744-683X

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (homogeneous); solar (photovoltaic); bio-inspired; charge transport; mesostructured materials; materials and chemistry by design; synthesis (novel materials); synthesis (self-assembly)