PVDF Surface Functionalization for Strong Rubber Adhesion
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Solution Overview
Problem
PVDF, a fluorinated semi-crystalline polymer, exhibits poor adhesion properties to rubbers due to its low surface energy, which is a challenge in applications requiring strong adhesion, such as in piezoelectric devices.
Innovation Solution
A method involving the introduction of oxygen-containing functional groups on the surface of PVDF followed by reaction with a compound containing thiocyanate groups, such as silane, to enhance adhesion to sulfur cross-linkable rubber compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVDF is used for its piezoelectric properties and chemical stability, then reliability is improved, but adhesion to rubber deteriorates due to low surface energy
Solution Approach 1:
The invention applies local quality by treating only the surface of the PVDF polymer with oxygen plasma, creating a localized modified layer with oxygen-containing functional groups. This surface treatment enhances adhesion to rubber while preserving the bulk piezoelectric properties and chemical stability of the PVDF material.
Solution Approach 2:
The oxygen-containing functional groups introduced by plasma treatment act as an intermediary between the PVDF surface and the rubber. These functional groups create chemical bonding sites that facilitate strong adhesion to the rubber component, bridging the incompatibility between the low-surface-energy PVDF and the rubber material.
2Strength
If adhesive layers are used to bond PVDF to rubber, then adhesion is improved, but electrical conductivity between piezoelectric layer and conductive layers deteriorates
Solution Approach 1:
The invention extracts the adhesive function from a separate adhesive layer and integrates it directly into the PVDF surface through plasma treatment. By introducing oxygen-containing functional groups directly on the PVDF surface, the adhesion property is built into the substrate itself, eliminating the need for intermediate adhesive layers that would block electrical conductivity.
Solution Approach 2:
The invention merges the structural function of the PVDF piezoelectric layer with the adhesive function by creating a surface layer with oxygen-containing functional groups. This combined structure simultaneously provides mechanical support, piezoelectric performance, and strong adhesion to rubber, while maintaining electrical conductivity pathways.
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 method achieves high adhesive strength between PVDF and rubber, improving the bonding properties without affecting the structural integrity of the PVDF polymer.
Implementation Method 1
treating the surfaces of a PVDF polymer or co-polymer film with oxygen plasma
Implementation Method 2
introducing oxygen-containing functional groups on the surface of the piezoelectric polymer
Implementation Method 3
reacting the oxygen-containing functional groups with a compound comprising thiocyanate groups
Implementation Method 4
cross-linking the rubber component
Data Source
AI summary
The present invention relates to a method for chemically adhering a diene rubber to a piezoelectric polymer, the method comprising the steps of: a) providing a piezoelectric polymer having at least one surface, b) providing a rubber component having at least one surface and comprising a sulfur cross-linkable rubber composition, c) introducing oxygen-containing functional groups on the at least one surface of the piezoelectric polymer, d) reacting the oxygen-containing functional groups with a compound comprising thiocyanate groups, and e) contacting the surface of the piezoelectric polymer obtained of step d) with the surface of the rubber component, and cross-linking.