Behavior of a smart one-way micro-valve considering fluid–structure interaction

Abstract

Smart hydrogels are soft materials which can be applied in sensors and actuators especially in microfluidics in which the fluid–structure interaction is important. In this work, first, the behavior of a one-way hydrogel micro-valve is investigated by considering the fluid–structure interaction effect for a specified geometry of the micro-valve. Second, both the fluid–structure interaction and non-fluid–structure interaction simulations are conducted to study the fluid flow effect on the operational parameters of the micro-valve. The obtained results show that the fluid–structure interaction effects are important and have a considerable influence on the micro-valve parameters especially on its closing temperature. Thereafter, a precise study on the micro-valve is executed by considering the micro-valve operational parameters such as inlet pressure, head size, crosslinking density, and breaking pressure at different temperatures. The results show the importance of considering the fluid–structure interaction effect in the design of these devices.

A review on swelling theories of pH-sensitive hydrogels

“…Functional hydrogel structures for flow control inside microfluidic channels originate from the pioneering works of Beebe et al (2000) by employing the effective photo-polymerization fabrication method (Bayat and Baghani, 2019; Beebe et al, 2000). Several designs have been presented for the microfluidic flow control (Kurnia et al, 2011; Mazaheri et al, 2018; Voigt et al, 2019). These devices also work based on the swelling behavior of the pH-sensitive hydrogels.…”

PH-sensitive hydrogel-based valves: A transient fully-coupled fluid-solid interaction study

“…In other words, not only the resultant fluid pressure is applied to the solid structure, but also regarding the deformation of the solid structure, the fluid domain is updated. Most of the previous FSI analyses have been carried out in the equilibrium states (Amiri and Mazaheri, 2020;Arbabi et al, 2017;Khanjani et al, 2020;Mazaheri et al, 2018;Zhang et al, 2012). However, the transient swelling process of hydrogels cannot be observed in such studies.…”

“…A change in the pH value of the water solution flowing through the channel can cause a significant deformation in the hydrogel valve; in response to even small pH variation, the pH-responsive hydrogel valve moves toward the valve neck and blocks the channel. This hydrogel-based valve type has been studied by Mazaheri et al (2018) for temperaturesensitive hydrogel in an equilibrium condition. However, in this study, the valve is considered to be made of a pHsensitive hydrogel, and the transient swelling of the hydrogel is examined in our paper.…”

Fluid-structure interaction simulations for a temperature-sensitive functionally graded hydrogel-based micro-channel

“…Apart from this, using smart hydrogels in microfluidics systems requires consideration of the fluid-structure interaction (FSI) effect due to the soft nature of these materials in most of the studies in recent related literature. The importance of consideration of the FSI effect in microfluidics was illustrated by researchers (Arbabi et al, 2017; Mazaheri et al, 2018; Zhang et al, 2012). In the same way, Zhang et al (2012) were the first researchers that studied FSI effects in pH-sensitive hydrogel micro-valve and demonstrated the coupling between the hydrogel deformation and the fluid flow pressure field.…”

“…Arbabi et al (2017) studied the FSI effect in a pH-sensitive micro-valve and presented a new arrangement for pH-sensitive micro-valves. Mazaheri et al (2018) investigated a one-way microvalve behavior through an FSI study and presented a comprehensive parametric study on the mentioned micro-valve. In addition, Bayat and Baghani (2019) presented coupled transient analysis of a pH-sensitive hydrogel micro-valve in FSI framework.…”