Droplet Generation in a Flow-Focusing Microfluidic Device with External Mechanical Vibration.

Zhaoqin Yin,Fubing Bao,Xiaohui Lin,Xiaoyan Gao,Zemin Huang

doi:10.3390/mi11080743

Abstract

The demand for highly controllable droplet generation methods is very urgent in the medical, materials, and food industries. The droplet generation in a flow-focusing microfluidic device with external mechanical vibration, as a controllable droplet generation method, is experimentally studied. The effects of vibration frequency and acceleration amplitude on the droplet generation are characterized. The linear correlation between the droplet generation frequency and the external vibration frequency and the critical vibration amplitude corresponding to the imposing vibration frequency are observed. The droplet generation frequency with external mechanical vibration is affected by the natural generation frequency, vibration frequency, and vibration amplitude. The droplet generation frequency in a certain microfluidic device with external vibration is able to vary from the natural generation frequency to the imposed vibration frequency at different vibration conditions. The evolution of dispersed phase thread with vibration is remarkably different with the process without vibration. Distinct stages of expansion, shrinkage, and collapse are observed in the droplet formation with vibration, and the occurrence number of expansion–shrinkage process is relevant with the linear correlation coefficient.

Highlights

The technology of dealing with fluids on a microscale have made microfluidics an important tool for many biological and chemical applications [1,2,3]
Jeong et al [15] employed a 3D flow-focusing microfluidic device to improve the stability of the submicron emulsion droplet generation, and the emulsion droplet could be controlled by the pressure ratio
The active methods involving electric, magnetic, laser, acoustic elements have the capacities of controlling the droplet formation and manipulating droplet transportation in a fast-responding and effective way [10], the requirement of new-sets of on-chip integration components dramatically raises the price of microfluidic device fabrication [11,25]

Summary

Introduction

The technology of dealing with fluids on a microscale have made microfluidics an important tool for many biological and chemical applications [1,2,3]. Zhu et al [11] introduced the mechanical vibration in a co-flow microfluidic device to investigate the formation frequency and uniformity of the dispersed droplets.

Results

Conclusion