Microcell Sealing via Phenethylamine Polymer Interpenetration

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Solution Overview

Problem

Existing methods for sealing microcells used in electrophoretic displays, such as those involving thermoplastic polymers, face issues like leakage due to solvation by the electrophoretic medium and decreased adhesion, leading to delamination and reduced performance over time.

Innovation Solution

A method involving a first mixture of phenethylamines, like dopamine, and water-swellable polymers, followed by a second hydrophilic polymer mixture to form a robust seal, ensuring interaction and interpenetration to create a durable barrier without the need for a physical lid in many cases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If thermoplastic polymers are used to seal microcells, then the sealing process is simple, but leakage occurs due to solvation by the electrophoretic medium and decreased adhesion leading to delamination

Engineering Contradiction:

Improvesealing process simplicityVSAvoidseal integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite sealing system consisting of a hydrophilic polymer coating applied to the microcell opening and a hydrophobic polymer sealing composition that bonds to both the hydrophilic coating and the microcell wall. This multi-material approach prevents solvation by the electrophoretic medium while maintaining strong adhesion, thereby resolving the contradiction between manufacturing simplicity and seal integrity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The hydrophilic polymer coating serves as an intermediary layer between the microcell wall and the hydrophobic sealing composition. This intermediate layer prevents direct contact between the electrophoretic medium and the sealing materials, eliminating solvation issues while maintaining bonding strength, thus resolving the reliability problem without complicating the manufacturing process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If thermoplastic polymers are used for sealing, then the process is straightforward, but adhesion decreases over time causing delamination

Engineering Contradiction:

Improvesealing process straightforwardnessVSAvoidseal durability

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent employs a composite sealing structure with a hydrophilic polymer coating on the microcell opening and a hydrophobic polymer sealing composition that bonds to both the coating and the microcell wall. This composite system provides long-term adhesion stability by preventing solvation and chemical degradation, thereby extending the seal's operational life without complicating the manufacturing process.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical parameters of the sealing system by using polymers with specific hydrophilic and hydrophobic properties. The hydrophilic coating resists solvation by the electrophoretic medium, while the hydrophobic sealing composition provides stable long-term adhesion. This parameter-based approach ensures durable sealing that maintains its properties over time without requiring complex manufacturing steps.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a robust seal is formed using phenethylamine and hydrophilic polymer mixtures, then adhesion and barrier properties improve, but the sealing process becomes more complex

Engineering Contradiction:

Improveseal strengthVSAvoidsealing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the sealing process into two distinct stages: first applying a hydrophilic polymer coating to the microcell opening, then applying a hydrophobic polymer sealing composition. This segmentation allows each layer to perform its specific function (adhesion promotion and solvation resistance), achieving robust sealing while keeping each individual step relatively simple and manageable.

Inventive Principle:

Principle #1Segmentation

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 provides a strong, defect-free seal with improved adhesion and barrier properties, enhancing the longevity and performance of electrophoretic displays by preventing leakage and maintaining structural integrity.

Implementation Method 1

comprising a phenethylamine and a first, water-swellable polymer; and after adding the fluid, a second mixture, comprising a second, hydrophilic polymer, is introduced, whereupon the first and second polymers interact to seal the container

Methodology Applied

Scientific EffectWater swelling: Hydrogel

Data Source

PatentEP3368946B1Methods for sealing microcell containers with phenethylamine mixtures

Publication Date: 2021.08.25 E INK CORP

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AI summary

A method for sealing a container having an opening by contacting the opening with a mixture including a phenethylamine and a first polymer, adding a fluid to be contained to the container, and then adding a second mixture, comprising a second polymer, whereupon an interaction between the first and second polymer mixtures result in a seal being formed over the opening, thereby containing the fluid. The first polymer is typically a water-swellable polymer and the second polymer is typically a hydrophilic polymer that will form an interpenetrating network with the swellable polymer.