Sacrificial Polymeric Sheet for Interconnected Microvascular Networks
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Solution Overview
Problem
Current methods for developing microvascular networks in synthetic composite materials are limited by the brittleness of hollow glass fibers, the inability to form networks from hollow polymeric fibers, and the lack of spatial interconnectivity in microfluidic channels, which restricts their use in complex architectures and large-scale production.
Innovation Solution
A thermally degradable polymeric sheet comprising poly(hydroxyalkanoate) and a metal, such as tin(II) oxalate, is used as a sacrificial layer within a composite material, which degrades at controlled temperatures to create interconnected microfluidic channels, allowing for the formation of complex in-plane architectures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hollow glass fibers are used to form microfluidic channels in composite materials, then the channels can provide repair functionality, but the brittleness of the glass fibers limits the shapes and lengths of channels that can be present
Solution Approach 1:
The patent changes the material parameter from brittle glass to flexible polymer, enabling a wide range of channel shapes and lengths while maintaining repair functionality. The polymer matrix allows for complex 3D architectures that were impossible with glass fibers.
Solution Approach 2:
The invention uses composite hollow fibers combining polymer and glass shell layers, leveraging the flexibility of polymer for shaping and the durability of glass for structural integrity, thus resolving the contradiction between adaptability and reliability.
2Adaptability or versatility
If hollow polymeric fibers are arranged to form microfluidic channels, then a wider variety of channel shapes can be achieved, but the individual hollow fibers cannot be used to form a network
Solution Approach 1:
The patent extracts the network formation capability from the fiber arrangement process by using a continuous sacrificial mandrel that defines the entire network topology before composite formation, ensuring both shape versatility and network integrity.
Solution Approach 2:
The sacrificial mandrel is pre-formed with the complete network architecture including all interconnections before the composite material is deposited around it, enabling complex network topologies to be reliably created without post-processing assembly.
3Manufacturing precision
If 3-D direct-write assembly technique is used to form microfluidic networks in polymeric matrix, then excellent spatial control is achieved, but the networks cannot survive the mechanical and thermal stresses of conventional composite forming processes
Solution Approach 1:
The microfluidic network is pre-formed as an integral part of the composite structure through the sacrificial mandrel technique during the composite manufacturing process itself, allowing the network to be embedded in the cured matrix before stress exposure, thus maintaining both spatial precision and stress resistance.
4Ease of manufacture
If sacrificial fibers are used to create microvascular networks, then microchannels can be formed, but the interconnections lack spatial interconnectivity and fluidic pathway redundancy
Solution Approach 1:
The sacrificial mandrel is pre-designed with the complete network topology including all branches and interconnections, enabling complex spatial architectures with multiple fluidic pathways to be formed in a single manufacturing step, thus achieving both ease of manufacture and spatial interconnectivity.
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 rapid production of microvascular systems with interconnected channels, providing enhanced fluidic pathway redundancy and mechanical integrity, suitable for applications like active cooling and self-healing, while reducing processing time and avoiding obstructions.
Implementation Method 1
heating the composite to a temperature from 100 to 250° C. for a time sufficient to form degradants from the sacrificial layer
Data Source
AI summary
A thermally degradable polymeric sheet, comprising: a poly(hydroxyalkanoate); and a metal selected from the group consisting of an alkali earth metal and a transition metal; where the volume fraction of the metal in the sheet is at least 0.1 vol %.