Deformable Valve for Capillary-Driven Microfluidic Flow Control
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Solution Overview
Problem
Existing microfluidic devices face challenges in developing simple, inexpensive, and easy-to-operate valves that are compatible with capillary-driven systems, as active valves require external actuation and power, while passive valves lack interactivity and have issues with air venting and complex fabrication.
Innovation Solution
A microfluidic device with a deformable valve that controls liquid flow by capillarity, featuring a hollow chamber wider than the microchannels, with walls that can change deformation states to alter capillary pressure, allowing for efficient liquid control without the need for external power or complex fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If active valves are used to control liquid flow, then flow control capability is improved, but device complexity and power consumption increase
Solution Approach 1:
The valve utilizes the liquid's own capillary pressure to drive the deformable wall and control flow, eliminating the need for external actuators or power sources. The system serves itself by using the flowing liquid to generate the actuation force needed to open or close the valve through capillary pressure changes.
Solution Approach 2:
The patent replaces traditional mechanical actuation systems (motors, pistons, springs) with a capillary-driven deformable wall mechanism. The deformable wall responds to capillary pressure changes without requiring mechanical actuators, thereby simplifying the device while maintaining flow control capability.
2Ease of manufacture
If passive valves are used to simplify fabrication, then manufacturing complexity is reduced, but interactivity and flow control capability are lost
Solution Approach 1:
The valve transitions from a static passive structure to a dynamic system where the deformable wall can change shape in response to capillary pressure variations. This dynamic response enables the valve to interact with the flowing liquid and control flow on-demand, while the overall structure remains simple to fabricate using standard microfluidic techniques.
3Use of energy by moving object
If capillary-driven flow is used to eliminate power requirements, then energy consumption is reduced, but flow control precision may be compromised
Solution Approach 1:
The valve controls flow by changing the physical parameter of the deformable wall (its shape/position) in response to capillary pressure changes. By carefully designing the wall's geometry and material properties, the system achieves precise flow control using only capillary-driven parameter changes without external power.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient liquid control with minimal power consumption, no dead volumes, fast switching times, and resistance to particles and dust, while avoiding the use of heat-sensitive or chemical-responsive materials, thus simplifying fabrication and operation.
Implementation Method 1
Liquid is pulled along the flow direction by capillarity substantially more in the second deformation state than in the first deformation state
Data Source
Figure 1.A~2.C
Figure 3.A~4
Figure 5.A~8.B
AI summary
The invention is notably directed to a microfluidic device (100) comprising: a first microchannel (31), a second microchannel (32), and a valve (50) comprising at least an input port (51) and an output port (52), said ports respectively connected to the first microchannel and the second microchannel, the valve designed to control a flow of a liquid (L) along a flow direction (z) defined by the ports, wherein the valve further comprises one or more walls (54, 56, 58, 20) joining the ports and defining a hollow chamber (53) that is wider than each of the microchannels in a direction perpendicular to the flow direction, said walls at least partly deformable along a deformation direction (- y) intersecting the flow direction, such that the walls can be given at least a first deformation state (S1) and a second deformation state (S2), the liquid being pulled along the flow direction substantially more in the second deformation state than in the first deformation state, by capillarity.