Dielectric Layer Copolymer Mesogenic Units Self-Alignment

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Solution Overview

Problem

Current methods for fabricating piezoelectric and flexoelectric devices using polymers face challenges such as difficulty in controlling poling processes, which can lead to burning and charring of polymeric films, and require structures with no inversion symmetry, limiting the application of flexoelectricity in centrosymmetric materials.

Innovation Solution

The development of dielectric devices using polymerizable compositions comprising a solvent and a combination of polymerizable mesogenic monomers that self-align on an oriented substrate without poling, allowing for the formation of thin piezoelectric and flexoelectric layers through alignment and polymerization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If poling is used to orient polymer crystallites, then piezoelectric and flexoelectric properties are achieved, but the process is difficult to control and can cause burning and charring of the polymeric film

Engineering Contradiction:
Improvepiezoelectric and flexoelectric propertiesVSAvoidburning and charring of polymeric film
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical/thermal poling process with a chemical approach using polymerizable mesogenic monomers that self-align through their inherent mesogenic properties during polymerization, eliminating the need for high-temperature poling that causes burning and charring

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter from post-polymerization poling to pre-polymerization self-alignment of mesogenic monomers, allowing orientation to occur during the polymerization process itself at lower temperatures, thus avoiding thermal damage to the polymer film

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If centrosymmetric materials are used, then flexoelectricity can be applied, but piezoelectricity requires structures with no inversion symmetry

Engineering Contradiction:
Improveapplication of flexoelectricity in centrosymmetric materialsVSAvoidpiezoelectric property requirement
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent creates a universal platform using polymerizable mesogenic monomers that can exhibit both piezoelectric and flexoelectric properties depending on the material system, allowing centrosymmetric materials to be utilized for flexoelectric applications while maintaining the capability for piezoelectric applications in non-centrosymmetric systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach enables the creation of dielectric layers that exhibit piezoelectric and flexoelectric properties without the need for poling, allowing for the use of centrosymmetric materials and reducing the risk of damage during the fabrication process, while also providing a flexible and efficient method for producing these devices.

Implementation Method 1

polymerizable mesogenic monomers that self-align on an oriented substrate without poling

Methodology Applied
Scientific EffectLiquid crystal alignment: Liquid Crystals

Implementation Method 2

polymerizing the aligned combination of polymerizable mesogenic monomers to form a dielectric layer

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 3

materials exhibiting flexoelectricity can have a spontaneous electrical polarization when induced by a strain gradient

Methodology Applied
Scientific EffectFlexoelectricity: Piezoelectric Effect

Data Source

PatentEP3673521B1Dielectric layer comprising copolymer with mesogenic units
Publication Date: 2023.08.09 PPG INDUSTRIES OHIO INC
  • EP3673521B1 patent drawingFigure 1
  • EP3673521B1 patent drawingFigure 2A~2B
  • EP3673521B1 patent drawing

AI summary

Self-aligning liquid crystal copolymers comprising two mesogenic repeating units are disclosed. The copolymers can exhibit piezoelectric and flexoelectric properties.