Microfluidic Valve Using Phase Transition Material and Lens
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Solution Overview
Problem
Conventional microfluidic devices face challenges in miniaturization and precise control of fluid flow due to the need for large amounts of paraffin wax and heaters, which complicates integration and slows down the melting process of wax valves, making it difficult to perform multiple step processes efficiently.
Innovation Solution
A microfluidic device with a valve made of a phase transition material that changes from a non-fluidic to a fluid phase upon energy application, using a lens to concentrate or diverge energy from an electromagnetic source, such as a laser, to control fluid flow, allowing for rapid melting and hardening of the valve within the channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of paraffin wax is used to close the channel, then the channel can be effectively sealed, but the heater capacity must be increased and the device cannot be miniaturized
Solution Approach 1:
The invention changes the material parameter from conventional paraffin wax to phase transition materials with lower melting points and higher melting enthalpies (such as fatty acid esters, waxes, or their mixtures). This parameter change allows the valve to achieve effective channel sealing with much smaller amounts of material, enabling miniaturization of the heater and overall device while maintaining reliable channel closure.
Solution Approach 2:
The invention utilizes phase transition materials that undergo solid-liquid phase change at specific temperatures. The valve material transitions from solid (blocking flow) to liquid (allowing flow) upon heating and back to solid when cooled. This phase transition mechanism enables effective channel control with minimal material volume, resolving the contradiction between sealing effectiveness and device size.
2Temperature
If a heater with large capacity is used to melt the paraffin wax, then the wax can be melted, but the device cannot be miniaturized and integration into existing systems becomes difficult
Solution Approach 1:
The invention changes the thermal parameters of the valve material by using phase transition materials with lower melting points and higher melting enthalpies compared to conventional paraffin wax. This allows a miniaturized heater to deliver sufficient energy density to melt the valve material effectively, enabling device miniaturization while maintaining melting capability.
Solution Approach 2:
The invention employs composite or mixed phase transition materials (such as mixtures of fatty acid esters and waxes) that can be tailored to have optimized melting characteristics. These composite materials provide both low melting points and high melting enthalpies, enabling effective valve operation with miniaturized heating elements and facilitating integration into compact existing systems.
3Reliability
If conventional paraffin wax is used for the valve, then the channel can be closed, but it takes a long time to melt and precise control of the opening time is difficult
Solution Approach 1:
The invention changes the thermal response parameters by selecting phase transition materials with appropriate melting points and melting enthalpies. These materials melt rapidly when heated and can be precisely controlled in terms of melting timing. The high melting enthalpy ensures complete phase transition while the tailored melting point enables precise temporal control, resolving the contradiction between reliable closure and fast, controllable opening.
4Device complexity
If the microfluidic device is miniaturized, then integration into existing systems becomes possible, but sufficient energy cannot be delivered to melt the valve material
Solution Approach 1:
The invention changes the energy parameters by using phase transition materials with high melting enthalpies but low melting points. This allows miniaturized devices to deliver sufficient energy density to melt the valve material effectively. The high melting enthalpy ensures complete phase transition with minimal material volume, while the low melting point reduces the total energy required, enabling successful miniaturization and system integration.
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 solution enables rapid and precise control of fluid flow, reduces manufacturing costs by eliminating the need for bulky lenses and barrels, and prevents operational errors from incomplete melting, facilitating efficient miniaturization and integration of microfluidic systems.
Implementation Method 1
a valve which controls flow of a fluid flowing along the channel and comprises a phase transition material which is in a non-fluidic phase at an ambient temperature and changes into a fluid phase upon application of energy
Implementation Method 2
a lens which is disposed on the substrate and adjusts a beam of the energy applied from an energy source to the valve
Implementation Method 3
The valve may include a plurality of minute heating particles that are diffused in the phase transition material and each absorb electromagnetic wave energy to emit heat
Data Source
AI summary
Provided is a microfluidic device and microfluidic system with the device. The microfluidic device includes a substrate; a channel formed in the substrate and in which a fluid can move; a valve controlling flow of a fluid flowing along the channel and including a phase transition material which can be melted by energy such as electromagnetic wave energy; and a lens disposed on the substrate and adjusting an irradiating region of the valve, onto which the energy is applied.