Stimuli-Responsive Microfluidic Valve for Integrated Flow Control
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Solution Overview
Problem
Current microfluidic devices require expensive external equipment for controlling liquid flows and have limited mechanical functionality, making them costly and unsuitable for industrial-scale production and market penetration due to integration challenges of active pumps and valves.
Innovation Solution
The use of liquid crystal networks or elastomers (LCN/LCE) with mechanical response to external stimuli, enabled by 4D printing, allows for the configuration of active microfluidic valves that can regulate fluid flow in response to changes in light, temperature, pH, or electromagnetic fields, integrating all functional elements into a single compact device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If active pumps and valves are integrated into the microfluidic chip, then the device functionality is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the valve structure and the LCP actuator into a single integrated component. The LCP material is directly formed within the microfluidic channel to create the valve, eliminating the need for separate actuators and reducing integration complexity while maintaining full functionality.
Solution Approach 2:
The LCP material serves multiple functions simultaneously: it acts as both the structural component of the valve and the actuating element. This multi-functionality reduces the number of separate components needed and simplifies the overall device architecture.
2Reliability
If external auxiliary equipment is used for controlling liquid flows, then the mechanical response capability is improved, but the cost and device size increase
Solution Approach 1:
The patent extracts the actuation function from external auxiliary equipment and relocates it directly into the microfluidic chip itself. The LCP material is integrated within the chip to provide the mechanical response capability, eliminating the need for external actuators and reducing overall device complexity.
Solution Approach 2:
The LCP material provides self-actuation capability within the microfluidic device. When exposed to external stimuli such as light or temperature changes, the LCP automatically changes its mechanical properties to open or close the valve, without requiring external mechanical actuators or complex control systems.
3Adaptability or versatility
If multiple material types are used in microfluidic devices, then the functional versatility is improved, but the processing difficulty and manufacturing cost increase
Solution Approach 1:
The patent employs LCP as a composite material that combines the properties of a structural material and an actuating material. This single composite material performs multiple functions that would traditionally require separate material layers or components, thereby reducing processing difficulty while maintaining functional versatility.
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
This approach enables precise control of fluid flow in microfluidic systems, allowing for complex geometries and functions, such as valve opening and fluid regulation, facilitating the development of stand-alone, industrially viable microfluidic devices with dynamic and reversible mechanical responses.
Implementation Method 1
The LCN and LCE can be obtained from a liquid crystal polymer (LCP) which is subjected to a polymer chain cross-linking process. This latter material can be applied in a controlled manner by additive layer manufacturing techniques and, once cross-linked, give rise to the LCN or LCE which allow the configuration of active microfluidic valves with mechanical response capability to changes in physicochemical magnitudes such as lighting, humidity, pH, temperature, or electromagnetic field, among others.
Implementation Method 2
the succession of filaments of the mechanically responsive material is arranged, in the mentioned flow rate, such that the variation in one or more of the physicochemical parameters causes a disruption in the molecular order of the LCP, contracting or expanding its polymer chains along a longitudinal or transversal direction of the filaments, and leading to an increase or reduction of the fluid flow rate.
Implementation Method 3
Said material comprises at least one LCP and is printed as a succession of one or more filaments, configuring a functional portion of the valve... the mechanical response capability of liquid crystal networks or elastomers (LCN or LCE) to certain external stimuli (light, temperature, etc.).
Data Source
AI summary
A microfluidic valve, includes arranging a substrate of a mechanically inert material to one or more physicochemical properties over time, configuring a structural portion of the valve; additive layer manufacturing to print, a succession of one or more filaments of a material with mechanical response to one or more of said physicochemical properties over time, preferably LCP, configuring a functional portion of the valve; and arranging the succession of filaments on the substrate, configuring a fluid flow rate through the valve using the application of an anti-adhesion treatment on one or more interfaces of said filaments and the substrate.