Crosslinked Fluorinated Copolymer Films With Solvent Resistance
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Solution Overview
Problem
Existing methods for crosslinking electroactive fluorinated copolymers, such as VDF-TrFE, often chemically modify the polymers, leading to a loss of their electroactive properties, and they are susceptible to dissolution by solvents used in subsequent layers of (opto)electronic devices.
Innovation Solution
A crosslinkable composition comprising electroactive fluorinated copolymers (P(VDF-TrFE) or P(VDF-TrFE-X) with bi- or polyfunctional (meth)acrylic monomers, a radical polymerization initiator, and additives, which form a crosslinked network without modifying the fluorinated polymer, allowing solvent resistance and pattern creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the electroactive fluorinated copolymer is crosslinked by chemical modification or copolymerization with comonomers, then solvent resistance is improved, but the electroactive properties (dielectric constant, polarization) are degraded
Solution Approach 1:
A silane coupling agent is used as an intermediary substance that forms a bridge between the fluorinated copolymer and the inorganic filler particles. The silane modifies the surface of the filler to create reactive sites that can bond with the polymer, thereby improving interfacial adhesion and solvent resistance without requiring chemical modification of the polymer backbone itself. This preserves the electroactive properties while achieving the desired stability.
Solution Approach 2:
The invention creates a composite material system combining fluorinated copolymer, inorganic filler particles, and silane coupling agent. The composite structure leverages the solvent resistance of the inorganic filler and the electroactive properties of the polymer matrix. The silane coupling agent ensures strong interfacial bonding between the filler and polymer, achieving both solvent resistance and preservation of electroactive functionality through the synergistic composite structure.
2Stability of the object's composition
If the electroactive fluorinated copolymer is crosslinked by peroxides, diamines, electron beam, or X-rays, then solvent resistance is improved, but the polymer structure is chemically modified causing loss of properties
Solution Approach 1:
The silane coupling agent acts as an intermediary that enables crosslinking and filler-polymer bonding through its dual reactivity: hydrolyzable groups that form bonds with inorganic filler surfaces and reactive groups that condense with hydroxyl groups on the filler. This intermediary mechanism achieves crosslinking and solvent resistance without direct chemical modification of the fluorinated copolymer chains, preserving their electroactive properties.
3Adaptability or versatility
If the copolymer is made crosslinkable by copolymerization with comonomers containing reactive groups, then crosslinking capability is improved, but reactive repeating units are created that interfere with crosslinking and degrade performance
Solution Approach 1:
The invention extracts the crosslinking functionality from the polymer chain itself and relocates it to the inorganic filler surface through silane modification. By taking out the need for reactive comonomers in the polymer and placing crosslinking sites on the filler particles instead, the system achieves crosslinking capability without introducing reactive repeating units into the polymer backbone that would interfere with crosslinking performance.
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 crosslinked films maintain the electroactive properties of the fluorinated copolymers, providing solvent resistance and enabling the formation of predefined patterns for complex (opto)electronic devices without degrading the polymer.
Implementation Method 1
at least one radical polymerization initiator, wherein the electroactive fluorinated copolymer is not capable of polymerization and/or crosslinking after activation of the radical polymerization initiator, and at least one bi- or polyfunctional (meth)acrylic monomer is capable of polymerization and crosslinking initiated after activation of the radical polymerization initiator
Data Source
Figure 1~2
AI summary
The invention relates to crosslinkable compositions based on electroactive fluorinated copolymers, crosslinked films obtained from such compositions and a method for preparing said films. The invention also relates to the use of the films as a dielectric layer in various (opto)electronic devices, i.e. piezoelectric, ferroelectric or pyroelectric ones.