Fluoropolymer Monolayer Coating for Durable Metal Adhesion
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Solution Overview
Problem
Fluoropolymers exhibit weak adhesion to metallic substrates, particularly when exposed to aqueous environments, and existing compositions are difficult to prepare, requiring specific solvents and equipment, leading to non-homogeneous coatings and environmental concerns.
Innovation Solution
A composition comprising a fluoropolymer, silicon-sulfur compound, and vinyl polymer in a solvent mixture, optimized for adhesion to metallic substrates, allowing for easy preparation with standard equipment and environmentally friendly processes, while maintaining electroactive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fluoropolymer is used with sulfur-containing adhesion promoters and silane agents, then adhesion strength to metallic substrates is improved, but the layer loses adhesion strength after soaking in aqueous solution
Solution Approach 1:
The patent uses a composite adhesion promoter system combining vinyl polymer (containing carboxyl or hydroxyl groups) with silicon-sulfur compound. This composite approach creates a synergistic effect where the vinyl polymer provides stable anchoring to the metal substrate through coordination bonds, while the silicon-sulfur compound forms a strong interface with the fluoropolymer layer, maintaining adhesion strength even after aqueous exposure.
Solution Approach 2:
The vinyl polymer acts as an intermediary layer between the metal substrate and the fluoropolymer. It contains functional groups that can coordinate with metal ions, creating a stable intermediate layer that prevents direct contact between water and the metal-fluoropolymer interface, thereby maintaining adhesion in humid environments.
2Ease of manufacture
If melt-processing is used to coat fluoropolymer onto substrate, then coating can be performed, but viscosity is high and shear rates are required resulting in non-homogeneous thin coatings
Solution Approach 1:
The patent changes the physical state parameter of the fluoropolymer from molten state to dissolved state. By dissolving the fluoropolymer in a solvent to create a solution with optimized concentration, the viscosity is reduced to a range that allows homogeneous coating at low shear rates, eliminating the need for high shear processing while achieving uniform thin films.
Solution Approach 2:
The patent replaces the mechanical shear-based coating process (requiring high shear rates) with a solution-based coating process. The solvent facilitates flow and distribution of the fluoropolymer at low shear rates, substituting the mechanical energy requirement with chemical solvation effects that enable homogeneous coating.
3Adaptability or versatility
If wide range of solvents are used with fluoropolymers, then solubility is achieved, but it is difficult to choose the right solvent and preparation is complex
Solution Approach 1:
The patent selects a specific solvent or solvent mixture with particular properties (polarity, boiling point, solubility parameters) that are locally optimized for dissolving the fluoropolymer and controlling the coating process. This targeted solvent selection provides the right balance of solubility, evaporation rate, and film formation characteristics without requiring trial and error with multiple solvents.
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 composition achieves high adhesion strength to metallic substrates, even in aqueous conditions, with thin, homogeneous coatings suitable for electronic applications, using traditional coating techniques and environmentally friendly methods.
Implementation Method 1
a material capable of forming a covalent bond with the electrode metal including a mercapto group as a functional group
Implementation Method 2
another route is to solubilize the polymer into a solvent as to obtain a liquid composition
Implementation Method 3
one route is to melt and process the polymer, another route is to solubilize the polymer into a solvent as to obtain a liquid composition
Data Source
AI summary
The invention concerns a composition comprising a fluoropolymer, a silicon-sulfur compound, a vinyl polymer consisting in carbon and hydrogen atoms, and optionally oxygen and/or nitrogen atoms, and a solvent or a mixture of solvents and methods for the preparation thereof and for preparing a coated substrate by applying said composition.