ORCID ID
Christopher L. Wirth: 0000-0003-3380-2029, Ryan, Shawn/0000-0003-2468-1827
Document Type
Article
Publication Date
2019
Publication Title
ACS Omega
Abstract
Active colloidal particles regularly interact with surfaces in applications ranging from microfluidics to sensing. Recent work has revealed the complex nature of these surface interactions for active particles. Herein, we summarize experiments and simulations that show the impact of charged nanoparticles on the propulsion of an active colloid near a boundary. Adding charged nanoparticles not only decreased the average separation distance of a passive colloid because of depletion attraction as expected but also decreased the apparent propulsion of a Janus colloid to near zero. Complementary agentbased simulations considering the impact of hydrodynamics for active Janus colloids were conducted in the range of separation distances inferred from experiment. These simulations showed that propulsion speed decreased monotonically with decreasing average separation distance. Although the trend found in experiments and simulations was in qualitative agreement, there was still a significant difference in the magnitude of speed reduction. The quantitative difference was attributed to the influence of charged nanoparticles on the conductivity of the active particle suspension. Follow-up experiments delineating the impact of depletion and conductivity showed that both contribute to the reduction of speed for an active Janus particle. The experimental and simulated data suggests that it is necessary to consider the synergistic effects between various mechanisms influencing interactions experienced by an active particle near a boundary.
Repository Citation
Issa, Marola W.; Baumgartner, Nicky R.; Kalil, Mohammed A.; Ryan, Shawn D.; and Wirth, Christopher L., "Charged Nanoparticles Quench the Propulsion of Active Janus Colloids" (2019). Mathematics and Statistics Faculty Publications. 309.
https://engagedscholarship.csuohio.edu/scimath_facpub/309
DOI
10.1021/acsomega.9b00765
Version
Publisher's PDF
Comments
https://pubs.acs.org/doi/pdf/10.1021/acsomega.9b00765?rand=0nl46y7c
This work was supported by the Cleveland State University Office of Research Startup Fund, the National Science Foundation CAREER Award, NSF no. 1752051, and an Undergraduate Summer Research Award (M.W.I.).