Flexible Conductive Polymer Films via Electrospun Nanofiber Embedding
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Solution Overview
Problem
Current transparent conductive films, such as those using indium tin oxide, are brittle and lose conductivity at small strains, making them unsuitable for flexible and stretchable electronic devices that require high levels of flexibility and durability, especially in roll-to-roll manufacturing processes.
Innovation Solution
The development of flexible, stretchable, and transparent hybrid polymer films comprising electrically conductive electrospun nanofibers embedded in solution-cast dielectric polymer films, using materials like poly(methyl methacrylate) or polyimide, which are produced through a combination of electrospinning and solution casting processes, allowing for the creation of conductive pathways without sacrificing flexibility or transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ITO is used to create transparent conductive films, then electrical conductivity and optical transparency are improved, but flexibility and stretchability deteriorate due to brittleness
Solution Approach 1:
The patent uses composite materials by combining conductive polymers (such as PEDOT:PSS, polyaniline, polypyrrole) with flexible polymer substrates (such as PMMA, polyimide, PDMS). This composite structure allows the film to maintain electrical conductivity through the conductive polymer pathways while gaining flexibility and stretchability from the polymer matrix, directly resolving the brittleness issue of pure ITO films
Solution Approach 2:
The patent changes the material parameters from inorganic ITO to organic conductive polymers, which fundamentally alters the mechanical properties. The conductive polymers can be processed in solution and formed into flexible films that can withstand bending and stretching, transforming the film from brittle to flexible while maintaining conductivity through controlled polymer morphology and composition
2Strength
If ITO layers are made thin to improve flexibility, then bendability is improved, but conductivity is lost at very small strains
Solution Approach 1:
The patent employs thin flexible polymer films containing conductive polymer networks that can bend and stretch without breaking. The flexible polymer matrix allows the thin film structure to deform elastically, while the conductive polymer pathways remain intact during bending, preventing conductivity loss that occurs in thin ITO layers
Solution Approach 2:
The flexible polymer substrate acts as an intermediary matrix that supports the conductive polymer pathways. This intermediary structure allows mechanical deformation to be accommodated without disrupting the conductive network, mediating between the need for flexibility and the requirement to maintain conductivity during bending
3Illumination intensity
If carbon nanotubes or graphenes are used to eliminate ITO, then transparency is improved, but continuous film formation requires complex transferring steps
Solution Approach 1:
The patent extracts the problematic transferring step from the manufacturing process by directly forming conductive polymer films on the final flexible substrate using solution casting or spin coating. This eliminates the need to transfer carbon nanotube or graphene films from temporary substrates, simplifying the manufacturing process while maintaining optical transparency
Solution Approach 2:
The patent replaces the mechanical transferring process with a chemical solution-based deposition method. Instead of mechanically transferring pre-formed nanomaterial films, the conductive polymers are deposited directly from solution onto the flexible substrate, substituting a complex mechanical transfer operation with a simpler solution processing step
4Ease of manufacture
If conventional coating processes are used to deposit conductive layers, then manufacturing is simplified, but stretchability to large strains is not achieved
Solution Approach 1:
The patent creates composite films where conductive polymers are embedded within a flexible polymer matrix that can accommodate large strains. This composite structure maintains the simplicity of solution-based coating processes while enabling stretchability, as the flexible matrix can deform elastically without breaking the conductive network
Solution Approach 2:
The patent changes the material composition from conventional inorganic or carbon-based conductive layers to intrinsically conductive polymers that can be processed from solution. This parameter change enables both simple solution casting and large stretchability, as the polymer chains can extend and reconfigure during stretching while maintaining conductivity
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
These films maintain conductivity and flexibility even under high levels of strain and repeated bending, offering improved performance compared to traditional ITO-based films, with surface resistivity and transmittance suitable for various electronic applications.
Implementation Method 1
The electrically conductive nanofiber, or nanofiber structure, can be electrospun from a suitable polymer solution that contains a suitable amount of, for example, at least one conductive material
Implementation Method 2
the flexible polymer film portion is form via a casting process to produce transparent films from, for example, polycarbonate, polyurethane and/or cyclopolyolefin polymer compositions
Data Source
AI summary
A method for producing flexible, stretchable transparent and highly electrically conducting hybrid polymer films includes embedding electrically conductive electrospun nanofibers in solution cast dielectric polymer films. The electrically conductive nanofiber, or nanofiber structure, can be electrospun from a suitable polymer solution that contains a suitable amount of, for example, at least one conductive material. The polymer film portion can be formed from poly(methyl methacrylate) (PMMA) or polyimide. The flexible polymer film portion can be a transparent film, made from, for example, polycarbonate, polyurethane and/or cyclopolyolefin polymer compositions.