Microfluidic Module Sealing With Ridge-Based Film Bonding
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Solution Overview
Problem
Existing microfluidic module sealing technologies face issues with air inclusions, fluidic short circuits, and channel blockages due to unevenness in the sealing process, which are exacerbated by the need for precise surface flatness and complex sealing film constructions.
Innovation Solution
Incorporating a sealing ridge that projects from the module surface and has a softening temperature below the sealing temperature, allowing the sealing film to adhere to the ridge and reduce dependence on surface evenness, thereby simplifying the sealing process and minimizing air inclusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal sealing is applied to seal the microfluidic cavity, then sealing is achieved, but air inclusions, capillary gaps, or fluidic short circuits occur due to surface unevenness
Solution Approach 1:
A sealing ridge is formed on the module body surface before the sealing process. This pre-formed ridge creates a localized sealing zone that compensates for surface unevenness, allowing the sealing film to be properly positioned and sealed without air inclusions or fluidic defects even on non-flat surfaces
Solution Approach 2:
The sealing ridge acts as an intermediary structure between the module body and the sealing film. It mediates the interface by providing a defined sealing surface that bridges the gap caused by surface unevenness, preventing direct contact issues between the sealing film and the irregular module body surface
2Reliability
If a height compensation layer is added to the sealing film to compensate for surface unevenness, then sealing quality improves, but the sealing film construction becomes more complex
Solution Approach 1:
Instead of modifying the sealing film to compensate for surface unevenness (adding height compensation layers), the approach is inverted by modifying the module body surface itself through the formation of a sealing ridge. This shifts the compensation function from the film side to the substrate side, simplifying the sealing film structure
3Reliability
If sealing pressure is increased to improve sealing on uneven surfaces, then sealing effectiveness improves, but the sealing layer penetrates into the microfluidic channels
Solution Approach 1:
The sealing ridge creates a localized sealing zone with concentrated pressure exactly where needed at the cavity opening. This local pressure concentration achieves effective sealing without requiring high overall pressure that would cause the sealing layer to penetrate into and block the microfluidic channels elsewhere
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 sealing ridge enhances sealing quality by reducing the risk of air inclusions and channel penetration, allowing for more efficient and reliable sealing on uneven surfaces, with reduced complexity and improved compatibility with various sealing films.
Implementation Method 1
The sealing layer has a softening temperature below a sealing temperature
Implementation Method 2
applying temperature and pressure in order to heat the sealing layer to the sealing temperature and to produce an adhesive bond between the sealing film and the module body
Data Source
AI summary
A method for producing a sealed microfluidic module which has a module body and a sealing film sealing a microfluidic cavity in a surface of the module body has providing the module body having the microfluidic cavity in a surface thereof and a sealing ridge at least partially surrounding the microfluidic cavity and projects from the surface, providing the sealing film having a sealing layer and an outer layer, the sealing layer having a softening temperature below a sealing temperature and the outer layer having a softening temperature above the sealing temperature, and sealing the microfluidic cavity with the sealing film by bringing the sealing layer of the sealing film into contact with the surface of the module body and applying temperature and pressure to heat the sealing layer to the sealing temperature and to produce an adhesive bond between the sealing film and the module body.