Study on pH-sensitive hydrogel micro-valves: A fluid–structure interaction approach

Abstract

Hydrogels are categorized as soft materials that undergo large deformation when they are subjected to even minor external forces. In this work, the performance of a variety of micro-valves, based on pH-sensitive hydrogel jackets coated on rigid pillars, is studied considering the gel deformation under fluid flow, employing fluid–structure interaction simulations. In this regard, an analytical solution to plane-strain inhomogeneous swelling of a cylindrical jacket is proposed. This is used as a tool to validate the finite element model. Then, a micro-valve consisting of one hydrogel jacket is studied in various inlet pressure and pH values performing fluid–structure interaction simulations. Thereafter, a variety of jacket patterns are investigated in order to identify the effects of the pattern on the micro-valve performance for various fluid stream pressures and pH values. The leakage pressure of the valves is also computed for each of the patterns. Fluid–structure interaction simulation is found to be essential to accurate design of the hydrogel-based microfluidic devices.

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

“…There are two general methods for FSI simulation: monolithic and partitioned. In this work, we use a two-way partitioned method in which the fluid and the solid domains are simulated separately in each increment while the interfacial conditions are interchanged between two simulations by MpCCI software (Arbabi et al, 2016). For both domains, the governing equations are the equation of motion.…”

“…They presented a simple design consisted of a cylindrical hydrogel jacket on a rigid core rested in a channel which could regulate the fluid pass through the channel. This design has been studied in various aspects by some researchers (Arbabi et al, 2016; Chester and Anand, 2011; Liu et al, 2002; Mazaheri et al, 2015; Wang et al, 2005). Thereafter, Kim and Beebe (2007) presented a one-way hydrogel micro-valve which can be employed in microfluidics as a check-valve which is investigated in this work in detail.…”

“…Zhang et al (2012) studied the FSI in pH-sensitive hydrogel micro-valves and showed the importance of interaction between hydrogel jacket and fluid flow. Also, Arbabi et al (2016) conducted an FSI simulation for the pH-sensitive hydrogel micro-valves for the Beebe valve. They suggested some new arrangements for the Beebe valve and consequently presented the FSI simulations for these arrangements.…”

Study of swelling behavior of temperature sensitive hydrogels considering inextensibility of network

“…These materials can be used as sensor and actuator simultaneously. Thus, they have a promising future for application in drug delivery systems [16], sensors and actuators [17][18][19][20][21] and microfluidics and micro-valves [22][23][24].…”

Computational investigation of magnetic hydrogels and elastomers

“…For applications in diverse areas including microfluidics and drug delivery, the hydrogel is often immersed in a moving fluid instead of still fluid, where the hydrostatic pressure may impede the hydrogel swelling by overcoming the osmotic pressure and it may cause the hydrogel to collapse [231]. A literature search shows that so far no effort has been done to reveal the responsive mechanism of the magnetic hydrogel under the coupled magneto-chemo-hydro-mechanical fields.…”