Solid-State Extrusion of Semi-Crystalline Fluoro-Polymer Films
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Solution Overview
Problem
Current methods for solid-state extrusion of semi-crystalline ferroelectric polymer films are limited to temperatures above the Curie transition temperature, making it difficult to process these materials below this critical temperature range.
Innovation Solution
A method involving compression of semi-crystalline fluoro-polymer materials at temperatures below the melting point, allowing for cooling between compression stages, and using co-extrusion substrates or mandrel expansion to produce films with enhanced crystallinity and ferroelectric properties, extending the processing range from the glass transition temperature to the melting temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solid-state extrusion is performed above the Curie transition temperature, then the polymer is easier to process due to lower crystallite modulus, but the ferroelectric properties are lost
Solution Approach 1:
The patent applies parameter changes by carefully controlling the temperature parameter during solid-state extrusion to remain below the Curie transition temperature (Tc) while still achieving adequate polymer chain mobility for processing. This allows the crystallite modulus to remain high but the process to proceed by controlling other parameters such as pressure and deformation rate, thereby preserving ferroelectric properties while achieving manufacturability
Solution Approach 2:
The patent employs dynamics by applying controlled mechanical deformation and pressure during extrusion to dynamically overcome the high stiffness of ferroelectric crystallites at temperatures below Tc. The dynamic application of stress and strain enables chain mobility and processing without requiring thermal softening that would lose ferroelectric properties
2Reliability
If solid-state processing is performed below the crystal-crystal transition temperature, then ferroelectric properties are preserved, but the high modulus crystallite structure prevents processing
Solution Approach 1:
The patent applies preliminary action by pre-conditioning the polymer material before extrusion through methods such as annealing or orientation treatments that prepare the crystallite structure for subsequent deformation. This preliminary preparation creates a more favorable initial state that enables processing below Tc while maintaining ferroelectric properties
Solution Approach 2:
The patent employs periodic action through cyclic deformation or oscillatory processing methods that temporarily soften the crystallite structure during processing intervals, then allow recovery of ferroelectric order between cycles. This periodic application of stress enables cumulative deformation while preserving the ferroelectric crystal structure
3Reliability
If compression is applied to increase crystallinity and ferroelectric properties, then material properties are improved, but processing complexity increases due to multiple compression stages
Solution Approach 1:
The patent applies merging by combining multiple compression and cooling stages into an integrated extrusion process where compression, cooling, and shaping occur in a unified sequence within a single processing operation. This consolidation achieves the desired crystallinity and ferroelectric properties while reducing overall process complexity compared to separate batch operations
Solution Approach 2:
The patent employs universality by designing a multi-functional processing system that simultaneously performs compression, cooling, shaping, and crystallization control in a single apparatus. This multi-functionality achieves improved material properties without proportionally increasing device complexity, as one system performs multiple necessary operations
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 formation of semi-crystalline fluoro-polymer films with improved crystallinity, ferroelectric, and piezoelectric properties, allowing for the production of films with higher Young's modulus and enhanced electrical properties compared to conventional methods.
Implementation Method 1
solid state extrusion of semi-crystalline fluoro-polymer films
Implementation Method 2
a crystal-crystal transition from a ferroelectric crystal form to a paraelectric crystal form at a transition temperature known as a Curie temperature, Tc
Implementation Method 3
Films with molecular orientation can be formed from semi-crystalline polymer films by biaxial tensile drawing
Implementation Method 4
The material may be cooled between compression stages
Data Source
AI summary
Disclosed herein is a method to produce a semi-crystalline fluoro-polymer film. A semi-crystalline fluoro-polymer material is used. The material is compressed to produce the film. During compression, the material is maintained at a temperature below the melting point of the material. The compression step can be cycled to allow cooling of the material between compression stages. Alternative methods are provided for compressing the material with a co-extrusion substrate, extruding the material and utilizing mandrel expansion for the material.