Thin Film Microfluidic Device via Direct Ink Writing
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Solution Overview
Problem
Existing techniques for fabricating microfluidic electronic devices are limited by laborious manual processes requiring clean-room facilities and vacuum systems, restricted material choices for substrates, and limitations in thickness, flexibility, and stretchability.
Innovation Solution
A method for forming a thin film-based microfluidic electronic device involves providing elastomeric thin film layers, depositing elastomer using direct ink writing to define microfluidic channels, covering with a sacrificial layer, injecting liquid metal, and electrically connecting it to electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft lithography is used to create elastomeric molds, then microfluidic devices can be fabricated, but the process requires clean-room facilities and vacuum systems making it laborious and complex
Solution Approach 1:
The patent extracts the microfluidic channel formation process from the complex soft lithography methodology by directly printing channels onto flexible substrates using inkjet printing technology, eliminating the need for elastomeric molds and clean-room facilities
Solution Approach 2:
The patent replaces the mechanical soft lithography process with inkjet printing technology, substituting a mechanically complex process involving molds and vacuum systems with a simpler digital printing approach that deposits material directly onto the substrate
2Reliability
If soft lithography is used to create elastomeric molds, then microfluidic devices can be fabricated, but the choice of substrate materials is restricted
Solution Approach 1:
The patent makes the substrate selection universal by enabling direct inkjet printing onto multiple flexible substrate types including plastics, metals, and ceramics, allowing the same fabrication process to work with diverse materials that have different mechanical and electrical properties
Solution Approach 2:
The patent changes the fundamental parameter of substrate compatibility by using inkjet printing technology that can accommodate various flexible substrates with different surface properties, thicknesses, and material compositions, rather than being limited to specific elastomeric materials
3Reliability
If soft lithography is used to create elastomeric molds, then microfluidic devices can be fabricated, but the device thickness is limited and flexibility is reduced
Solution Approach 1:
The patent employs flexible thin films as substrates for direct inkjet printing, enabling the fabrication of ultra-thin microfluidic devices that maintain high flexibility and stretchability, with device thickness limited only by the substrate thinness rather than mold constraints
Solution Approach 2:
The patent segments the microfluidic device into thin, flexible layers that can be independently optimized, allowing each layer to be extremely thin while maintaining structural integrity through the printing process and material selection
4Adaptability or versatility
If liquid metal is injected into microchannels, then stretchable electronic devices can be fabricated, but the oxide skin on liquid metal surface increases contact resistance
Solution Approach 1:
The patent converts the harmful oxide skin formation into a beneficial process by using plasma treatment to deliberately create a controlled oxide layer that improves adhesion between the liquid metal and surrounding materials, while maintaining electrical conductivity through careful control of oxidation conditions
Solution Approach 2:
The patent uses plasma as a strong oxidant to accelerate and control the oxidation of liquid metal surfaces, creating a thin, uniform oxide layer that enhances adhesion and can be subsequently reduced or managed to maintain electrical conductivity in the stretchable device
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 the creation of fully-stretchable and flexible microfluidic electronic devices that minimize mechanical mismatch with soft biological tissues, allowing for skin-contact and implantable applications without the need for clean-room facilities.
Implementation Method 1
their surface rapidly reacts with oxygen to form about 1-nm-thick skin of gallium oxide (primarily Ga2O3) when exposed to air
Implementation Method 2
depositing elastomer on the first elastomeric thin film by direct ink writing to form an elastomeric structure configured to define a microfluidic channel
Data Source
AI summary
There is provided a method of forming a thin film-based microfluidic electronic device. The method includes: providing a first elastomeric thin film layer on a substrate; depositing a first elastomer on the first elastomeric thin film by direct ink writing to form an elastomeric structure configured to define a microfluidic channel on the first elastomeric thin film layer; providing a second elastomeric thin film layer over the elastomeric structure to cover the microfluidic channel; providing a sacrificial layer on the second elastomeric thin film; depositing liquid metal into the microfluidic channel to form a conductor in the microfluidic channel; and electrically connecting the conductor to an electronic component. The thin film-based microfluidic electronic device is a tissue or skin adhesive sensor including a skin adhesive acoustic device.