Valve Unit with Phase Transition Material for Microfluidic Control
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Solution Overview
Problem
Conventional micro-valve units for controlling fluid flow in microchannels are difficult to miniaturize and precisely control due to the presence of air pumps and heating plates, and they take a long time to close the channel by re-solidifying melted paraffin wax.
Innovation Solution
A valve unit incorporating a phase transition material with heat generation particles that closes the channel upon irradiation with electromagnetic waves, such as a laser beam, allowing for miniaturization and precise control of fluid flow by melting and expanding the valve filler to block the channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air pump and heating plate are provided on the substrate, then the valve unit can control fluid flow by melting and re-solidifying paraffin wax, but it becomes difficult to miniaturize and fabricate the substrate
Solution Approach 1:
The patent extracts the air pump and heating plate from the substrate, eliminating these bulky components. Instead, the invention uses a valve filler containing phase transition material and heat generation particles that can be directly actuated by electromagnetic waves, thereby achieving fluid flow control without requiring external pumping and heating devices on the substrate.
Solution Approach 2:
The patent replaces the mechanical system (air pump and heating plate) with an electromagnetic system. Heat generation particles dispersed in the phase transition material convert electromagnetic wave energy directly into heat, melting the phase transition material to control fluid flow. This substitution eliminates the need for mechanical components and enables substrate miniaturization.
2Reliability
If paraffin wax is melted and directed to the channel by air expansion, then the channel can be closed, but it takes a relatively long time to close the channel by re-solidifying the paraffin wax
Solution Approach 1:
The patent employs periodic action through electromagnetic wave irradiation to rapidly heat and melt the phase transition material in the valve filler. By controlling the timing and duration of electromagnetic wave application, the system can quickly transition the valve filler between solid and liquid states, enabling precise and rapid channel closure without the time delay associated with natural re-solidification.
Solution Approach 2:
The patent changes the physical state parameter of the valve filler material by applying electromagnetic wave energy. The heat generation particles convert electromagnetic energy to thermal energy, rapidly changing the temperature and phase of the phase transition material from solid to liquid, which quickly blocks the channel. This parameter change approach eliminates the slow re-solidification process of conventional paraffin wax systems.
3Reliability
If conventional valve unit design is used, then fluid flow can be controlled, but it is difficult to precisely control the closing timing of the channel
Solution Approach 1:
The patent implements feedback control through the direct coupling of electromagnetic wave irradiation and phase transition material response. The electromagnetic waves provide immediate heating when applied, and the phase transition material responds instantaneously by melting or solidifying, creating a tightly coupled control system. This allows precise timing control of channel closure by simply controlling the timing of electromagnetic wave application, with the system naturally providing feedback through the phase transition process.
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
Enables rapid and precise control of fluid flow in microfluidic systems, facilitating the integration of biochemical reaction substrates and reducing the size of the reaction apparatus while ensuring timely channel closure.
Implementation Method 1
the heat generation particles are dispersed in the phase transition material and generate heat upon an application of electromagnetic wave energy
Implementation Method 2
the phase transition material melts and expands upon an application of heat which is generated by the heat generation materials
Data Source
AI summary
Provided are a valve unit and a reaction apparatus having the valve unit. The valve unit includes a phase transition material, which melts and expands upon an application of the electromagnetic waves to the valve filler, and the valve filler is directed into the channel through the connection passage and closes the channel. The valve unit also includes heat generation particles, which are dispersed in the phase transition material and generate heat upon an application of electromagnetic wave energy.