Precise manipulation of longitudinal dynamic self-assembly of particles in the viscoelastic fluid within a straight microchannel

The lack of a simple operable method for longitudinal dynamic self-assembly of particles in a microchannel is one of the main problems in applying this technology to a wide range of researches, such as biomedical engineering, material science, and computation. Herein, a viscoelasticity-induced trapping microfluidic system for flowing particles is proposed to increase the maneuverability of longitudinal dynamic self-assembly of particles and achieve real-time control of the interparticle spacings and the frequency of particles passing through the outlet. Two kinds of functional microstructures and a side-channel were designed to preprocessing the randomly distributed particles to make particles no aggregation and evenly distributed and realize real-time control of the particle volume concentration. Randomly distributed particles could be focused into a line and become equally spaced in the center axis of a straight microchannel under the balance of the elastic force and the viscoelasticity-induced effective repulsive force. Besides, a finite element method model is established to analyze the processes of particles flowing in each functional microstructure. Therefore, a step forward in this microfluidic technology can provide significant promotion for a wide range of researches.