Solvent-Based Fluoropolymer Coating for Metal-Core Piezoelectric Fibers

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods struggle to achieve optimal adhesion of fluoropolymer coatings to bare, electrically conductive metal filaments for piezoelectric fibers, requiring complex processes like electrowetting and high electrical voltages, and result in non-uniform polymer layers that are not suitable for thin, flexible applications.

Innovation Solution

A solvent-based coating formulation comprising P(VDF-TrFE) copolymer, surfactant, and adhesion promoter is used to create a continuous coating process that ensures uniform adhesion to metal cores, allowing for thin, flexible piezoelectric fibers without prior enameling or cladding, using a simple and industrially viable method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If electrowetting process with high electrical voltages is used to coat fluoropolymer on metal core, then adhesion of polymer layer to metal filament is improved, but device complexity and process difficulty increase

Engineering Contradiction:

Improveadhesion of polymer layer to metal filamentVSAvoidprocess complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent introduces a specific solvent-based fluoropolymer formulation as an intermediary medium that enables adhesion without requiring complex electrowetting equipment. The formulation contains fluoropolymer dissolved in a volatile solvent with specific properties that facilitate spontaneous adhesion to the metal core during the coating process, eliminating the need for high voltage electrical fields

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the electrical field-based electrowetting mechanism with a chemical/solvent-based coating mechanism. The solvent-based formulation allows the fluoropolymer to adhere to the metal core through evaporation and bonding mechanisms rather than electrical forces, substituting a complex electrical system with a simpler chemical process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If melt coating technique is used to coat piezoactive polymer on metal core, then coating process is simplified, but coating thickness becomes excessive (greater than 100 μm) and centering becomes difficult

Engineering Contradiction:

Improvecoating process simplicityVSAvoidcoating thickness control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the physical state parameter of the fluoropolymer from molten state (melt coating) to dissolved state (solvent-based coating). This parameter change allows for precise control of coating thickness through solvent evaporation rates and formulation concentration, enabling thin uniform coatings of 5-50 μm rather than the excessive thicknesses produced by melt coating

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies a controlled amount of solvent-based formulation that evaporates partially during the coating process, leaving behind the desired thin polymer layer. This partial evaporation action allows precise thickness control without requiring complex centering mechanisms or multiple coating passes

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If conductive polymer compounds are used to ensure electrical conductivity, then electrical conductivity is improved, but electrical conductivity decreases greatly when material is used in filament form due to filler alignment

Engineering Contradiction:

Improveelectrical conductivityVSAvoidelectrical conductivity stability in filament form

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent extracts the conductive metal core from the polymer matrix structure and uses it as the central element around which the fluoropolymer coating is applied. This extraction eliminates the problem of conductive filler alignment in the polymer, as the metal core provides inherent conductivity without being subject to spinning-induced alignment effects that reduce conductivity in filament form

Inventive Principle:

Principle #2Taking out (Extraction)

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 process achieves uniform, adhesive fluoropolymer layers of 5-100 μm thickness with improved electrical conductivity and mechanical flexibility, enabling efficient piezoelectric response and industrial scalability.

Implementation Method 1

a P(VDF-TrFE) copolymer solution at 10-30% by mass in a volatile solvent

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

b) a surfactant

Methodology Applied

Scientific EffectSurfactant: Surfactant

Implementation Method 3

c) an adhesion promoter

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 4

multicomponent fibers with a piezoelectric effect, comprising an electroactive fluoropolymer shell which adheres to a metal core

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS12376494B2Polymer formulation for coating a metal core

Publication Date: 2025.07.29 ARKEMA FRANCE SA

AI summary

Multicomponent fibers with a piezoelectric effect, including an electroactive fluoropolymer shell which adheres to a metal core. Also, a solvent-based fluoropolymer formulation which makes it possible to obtain optimum adhesion to a bare, electrically conductive metal filament. Also, a process for manufacturing these composite fibers, and also their uses in varied sectors of technical textiles, filtration and in electronics.