Active matter on asymmetric substrates

C. J. Olson Reichhardt; J. Drocco; T. Mai; M. B. Wan; C. Reichhardt

doi:10.1117/12.897424

9 September 2011 Active matter on asymmetric substrates

C. J. Olson Reichhardt, J. Drocco, T. Mai, M. B. Wan, C. Reichhardt

Proceedings Volume 8097, Optical Trapping and Optical Micromanipulation VIII; 80970A (2011) https://doi.org/10.1117/12.897424
Event: SPIE NanoScience + Engineering, 2011, San Diego, California, United States

Abstract

For collections of particles in a thermal bath interacting with an asymmetric substrate, it is possible for a ratchet effect to occur where the particles undergo a net dc motion in response to an ac forcing. Ratchet effects have been demonstrated in a variety of systems including colloids as well as magnetic vortices in type-II superconductors. Here we examine the case of active matter or self-driven particles interacting with asymmetric substrates. Active matter systems include self-motile colloidal particles undergoing catalysis, swimming bacteria, artificial swimmers, crawling cells, and motor proteins. We show that a ratchet effect can arise in this type of system even in the absence of ac forcing. The directed motion occurs for certain particle-substrate interaction rules and its magnitude depends on the amount of time the particles spend swimming in one direction before turning and swimming in a new direction. For strictly Brownian particles there is no ratchet effect. If the particles reflect off the barriers or scatter from the barriers according to Snell's law there is no ratchet effect; however, if the particles can align with the barriers or move along the barriers, directed motion arises. We also find that under certain motion rules, particles accumulate along the walls of the container in agreement with experiment. We also examine pattern formation for synchronized particle motion. We discuss possible applications of this system for self-assembly, extracting work, and sorting as well as future directions such as considering collective interactions and flocking models.

Citation Download Citation

C. J. Olson Reichhardt, J. Drocco, T. Mai, M. B. Wan, and C. Reichhardt "Active matter on asymmetric substrates", Proc. SPIE 8097, Optical Trapping and Optical Micromanipulation VIII, 80970A (9 September 2011); https://doi.org/10.1117/12.897424

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available