Acceleration of absolute negative mobility.
Recently, the counter intuitive migration phenomenon of absolute negative mobility (ANM) has been demonstrated to occur for colloidal particles in a suitably arranged post array within a microfluidic device [1]. This effect is based on the interplay of Brownian motion, nonlinear dynamics induced through microstructuring, and nonequilibrium driving, and results in a particle movement opposite to an applied static force. Simultaneously, the migration of a different particle species along the direction of the static force is possible [19], thus providing a new tool for particle sorting in microfluidic device format. The so far demonstrated maximum velocities for micrometer-sized spheres are slow, i. e., in the order of 10 nm per second. Here, we investigate numerically, how maximum ANM velocities can be significantly accelerated by a careful adjustment of the post size and shape. Based on this numerical analysis, a post design is developed and tested in a microfluidic device made of PDMS. The experiment reveals an order of magnitude increase in velocity.
Regtmeier
Jan
J
Experimental Biophysics and Applied Nanoscience, Physics Department, Bielefeld University, Bielefeld, Germany.
Grauwin
Sebastian
S
Eichhorn
Ralf
R
Reimann
Peter
P
Anselmetti
Dario
D
Ros
Alexandra
A
D000054:Acceleration; D003102:Colloids / Q000737:chemistry*; D004058:Diffusion; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D009038:Motion; D052638:Particulate Matter / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry
D003102:Colloids; D052638:Particulate Matter; D010710:Phosphates