PVDF-TrFE Copolymer End Group Exchange for Ferroelectric Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High molecular weight PVDF-TrFE polymers are challenging to synthesize and process due to low solubility and high viscosity, making it difficult to achieve ferroelectric properties comparable to high molecular weight polymers in printed memory technology, while low molecular weight polymers are desirable for easier processing but often lack these properties.
Innovation Solution
Exchanging the iodine end group of PVDF-TrFE copolymers with hydrogen using a tin hydride complex, such as tributyltin hydride, to reduce molecular weight without compromising ferroelectric properties, resulting in a polymer with improved crystallinity and lower drive voltage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high molecular weight PVDF-TrFE polymer is used, then ferroelectric properties are improved, but solubility decreases and viscosity increases making processing difficult
Solution Approach 1:
The patent changes the molecular weight parameter of the PVDF-TrFE polymer from high to low range, while compensating for the loss in ferroelectric properties through end group modification. This parameter change enables better solubility and processability while maintaining acceptable ferroelectric performance through the specific end group exchange reaction.
2Ease of manufacture
If low molecular weight PVDF-TrFE polymer is used, then solubility and processability are improved, but ferroelectric properties deteriorate
Solution Approach 1:
The patent applies local quality modification by specifically targeting the end groups of the polymer chains for chemical modification while leaving the bulk polymer structure unchanged. The end group exchange reaction introduces specific functional groups that compensate for the reduced molecular weight, thereby maintaining ferroelectric properties despite using low molecular weight polymer for improved processing.
Solution Approach 2:
The patent uses an intermediary chemical reaction process (end group exchange with tributyltin hydride) to modify the polymer ends. This intermediary step transforms the iodine end groups into hydrogen-terminated ends, which acts as a mediator to restore ferroelectric properties in low molecular weight polymers without affecting their inherent solubility and processability advantages.
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 method enables the production of low molecular weight PVDF-TrFE copolymers with enhanced ferroelectric properties, suitable for electronic devices, offering improved solubility and processing advantages while maintaining performance comparable to high molecular weight polymers.
Implementation Method 1
Exchanging the iodine end group of PVDF-TrFE copolymers with hydrogen using a tin hydride complex, such as tributyltin hydride
Data Source
Figure 1
Figure 2
AI summary
A method of exchanging or transforming end groups in and/or improving the ferroelectric properties of a PVDF-TrFE co-polymer is disclosed. A bulky or chemically dissimilar end group, such as an iodine, sulfate, aldehyde or carboxylic acid end group, may be transformed to a hydrogen, fluorine or chlorine atom. A method of making a PVDF-TrFE co- polymer is disclosed, including polymerizing a mixture of VDF and TrFE using an initiator, and transforming a bulky or chemically dissimilar end group to a hydrogen, fluorine or chlorine atom. A PVDF-TrFE co-polymer or other fluorinated alkene polymer is also disclosed. The co-polymer may be used as a ferroelectric, electromechanical, piezoelectric or dielectric material in an electronic device.