The Deformation of Polydimethylsiloxane (PDMS) Microfluidic Channels Filled with Embedded Circular Obstacles under Certain Circumstances.

Changhyun Roh,Jaewoong Lee,Chankyu Kang

doi:10.3390/molecules21060798

Abstract

Experimental investigations were conducted to determine the influence of polydimethylsiloxane (PDMS) microfluidic channels containing aligned circular obstacles (with diameters of 172 µm and 132 µm) on the flow velocity and pressure drop under steady-state flow conditions. A significant PDMS bulging was observed when the fluid flow initially contacted the obstacles, but this phenomenon decreased in the 1 mm length of the microfluidic channels when the flow reached a steady-state. This implies that a microfluidic device operating with steady-state flows does not provide fully reliable information, even though less PDMS bulging is observed compared to quasi steady-state flow. Numerical analysis of PDMS bulging using ANSYS Workbench showed a relatively good agreement with the measured data. To verify the influence of PDMS bulging on the pressure drop and flow velocity, theoretical analyses were performed and the results were compared with the experimental results. The measured flow velocity and pressure drop data relatively matched well with the classical prediction under certain circumstances. However, discrepancies were generated and became worse as the microfluidic devices were operated under the following conditions: (1) restricted geometry of the microfluidic channels (i.e., shallow channel height, large diameter of obstacles and a short microchannel length); (2) operation in quasi-steady state flow; (3) increasing flow rates; and (4) decreasing amount of curing agent in the PDMS mixture. Therefore, in order to obtain reliable data a microfluidic device must be operated under appropriate conditions.

Highlights

Microfluidic devices have attracted considerable attention for many evolutional aspects of applied sciences and engineering because of their actuated controls of micro-scale fluid behaviors in miniaturized devices [1,2]
The results showed the distribution of PDMS bulging in which the position was far away results distribution ofof bulging in which the position wasPDMS
The characteristic features of PDMS bulging in microfluidic channels are a function of the applied flow rate, operation flow conditions, microfluidic channel geometry and mixing ratios of PDMS mixture when the fluid-flow was discharged completely from a porous medium

Summary

Introduction

Microfluidic devices have attracted considerable attention for many evolutional aspects of applied sciences and engineering because of their actuated controls of micro-scale fluid behaviors in miniaturized devices [1,2]. An understanding of liquid flow through microchannels or microstructures plays a key role in the accurate and economic operation of microfluidic devices [4]. Fluid flow in porous media on the micro-scale has been applied in micro-reactors [14], micro-separators [15], micro-heat exchangers [16], micro-pumps [17], and micro-filters [18]. Despite their widespread applications, increasing the shear force near microstructures in porous media leads to augmented pressure drops [19]. The optimal design of the microstructure-integrated microchannel assembly in microfluidic systems will increase its efficiency

Methods

Discussion

Conclusion