VDF-TrFE-CTFE Terpolymer Films for High Modulus Actuation
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Solution Overview
Problem
Existing VDF/TrFE-based polymers have relatively low elastic modulus, making them difficult to handle and transform, especially when in the form of thin films, which limits their applications in electroactive systems.
Innovation Solution
A terpolymer system with a molar ratio of VDF:TrFE:CTFE ranging from 55:45 to 65:35 and a CTFE proportion of 1.5 to 4.5%, produced through suspension polymerization, achieving a high elastic modulus of at least 0.5 GPa and a thickness of less than 30 µm, suitable for thin films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the film thickness is reduced to enable low voltage activation, then the electrical voltage requirement decreases, but the film rigidity and handling ease deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by incorporating CTFE monomer at specific proportions (1-13 mol%) alongside VDF and TrFE. This compositional parameter change increases the elastic modulus and rigidity of the polymer chains, allowing thin films to maintain structural integrity while enabling low voltage operation through reduced thickness
Solution Approach 2:
The patent creates a composite polymer system by combining three different monomer units (VDF, TrFE, and CTFE) into a terpolymer structure. This composite material approach allows the film to simultaneously achieve the desired thinness for low voltage activation and the necessary rigidity through the synergistic properties of the combined monomer units
2Strength
If the CTFE content is increased to improve elastic modulus, then the rigidity increases, but the electrostrictive performance deteriorates
Solution Approach 1:
The patent optimizes the CTFE content parameter within a specific range (1-13 mol%, preferably 3-10 mol%). This precise parameter control ensures that the elastic modulus is sufficiently increased for handling ease, while the electrostrictive performance is preserved by not exceeding the optimal CTFE concentration threshold
3Ease of manufacture
If conventional polymerization methods are used, then the production process is established, but the monomer distribution homogeneity deteriorates
Solution Approach 1:
The patent employs preliminary action by pre-mixing all three monomers (VDF, TrFE, and CTFE) in the desired proportions before initiating polymerization. This pre-mixing step ensures uniform distribution of monomers throughout the reaction mixture, which leads to homogeneous polymer composition and consistent material properties in the final product
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 resulting terpolymer films exhibit enhanced elastic modulus and electrostrictive deformation, enabling easier manipulation and further processing, such as metallization, while reducing energy consumption due to a dielectric constant less than 40, and are manufactured using a continuous monomer addition process for improved homogeneity and reproducibility.
Implementation Method 1
ferroelectric and ferroelectric relaxor materials that generate mechanical actuation induced by an external electric field
Implementation Method 2
Suspension polymerization, solution polymerization, and emulsion polymerization are cited as suitable polymerization processes
Data Source
AI summary
The invention relates to a polymer comprising structural units of vinylidene fluoride, trifluoroethylene and chlorotrifluoroethylene, the molar ratio between the vinylidene fluoride and the trifluoroethylene in the polymer being between 55:45 and 65:35, and the molar proportion of the structural units of chlorotrifluoroethylene in the polymer being between 1.5 and 4.5 %. The invention also relates to various items comprising said polymer, such as films, fibres, extruded plates and moulded items.