2018/01/10 by Du, Yunfei, Hou, Zhonghuai
#FOS: Physical sciences #Soft Condensed Matter (cond-mat.soft)
paper · doi:10.48550/arxiv.1801.03279
The diffusion behavior of an active Brownian particle (ABP) in polymer solutions is studied using Langevin dynamics simulations. We find that the long time diffusion coefficient D can show a non-monotonic dependence on the particle size R if the active force Fa is large enough, wherein a bigger particle would diffuse faster than a smaller one which is quite counterintuitive. By analyzing the short time dynamics in comparison to the passive one, we find that such non-trivial dependence results from the competition between persistence motion of the ABP and the length-scale dependent effective viscosity that the particle experienced in the polymer solution. \textcolorblackWe have also introduced an effective viscosity ηeff experienced by the ABP phenomenologically. Such an active ηeff is found to be larger than a passive one and strongly depends on R and Fa\textcolormagenta. In addition, we find that the dependence of D on propelling force Fa presents a well scaling form at a fixed R and the scaling factor changes non-monotonically with R. Such results demonstrate that active issue plays rather subtle roles on the diffusion of nano-particle in complex solutions.