Controllable Transport and Size Segregation of Tiny Particles Harnessing Noise in 2D Brownian Motor System

Controllable transport and size segregation of tiny particles following the Brownian motor mechanism are investigated with pseudo-particle modeling (PPM), a simplified molecular simulation approach, in which the liquid surrounding the Brownian particle is discretized into many pseudo particles and naturally introduces thermal noise by hard-sphere interaction between the pseudo particles. An asymmetric periodic potential is applied to the Brownian particles acting as a flashing ratchet model. The macroscopic directional motion of a single Brownian particle in external non-equilibrium fluctuation is reproduced well by the method. Illustratively, the PPM method is successfully employed to conduct the simulations of Brownian motor and testify the adaptability of the method. The segregation of different-sized particles is also studied by varying the size ratio and operation conditions, such as temperature. The simulations will help a quantitative design of Brownian motors and their application in particle transport, separation, and segregation.