Liquid Crystal Composition for Cissing-Free Optical Film Alignment
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Solution Overview
Problem
Existing liquid crystal compositions suffer from cissing during formation of the liquid crystal cured layer and degraded alignment properties due to the structure of the surfactant used, which affects the uniformity and performance of optical films in image display devices.
Innovation Solution
A liquid crystal composition is formulated by blending a copolymer surfactant with specific repeating units, including branched Si structures and ring structures, to reduce surface tension and improve compatibility with liquid crystal compounds, thereby suppressing cissing and enhancing alignment properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a liquid crystal composition containing a conventional surfactant is used to achieve uniform coating, then coating uniformity is improved, but cissing occurs during formation of the liquid crystal cured layer and alignment properties are degraded
Solution Approach 1:
The invention changes the chemical structure parameters of the surfactant by specifying a copolymer with repeating units containing both hydrophilic groups (ethylene oxide, propylene oxide) and hydrophobic groups (aromatic rings, cycloalkane rings). This structural parameter change enables the surfactant to achieve both uniform coating distribution and compatibility with liquid crystal compounds, preventing cissing and maintaining alignment properties.
Solution Approach 2:
The invention uses a copolymer surfactant that combines multiple functional groups (hydrophilic ether groups and hydrophobic aromatic/cycloalkane rings) into a single composite molecular structure. This composite structure allows the surfactant to simultaneously perform coating uniformity functions and maintain liquid crystal compatibility, resolving the contradiction between coating quality and alignment properties.
2Ease of manufacture
If a surfactant with simple structure is used to reduce complexity, then ease of manufacture is improved, but cissing occurs and alignment properties are degraded
Solution Approach 1:
The invention specifies detailed structural parameters for the surfactant repeating units, including the presence of aromatic rings, cycloalkane rings, and ether groups in specific configurations. These parameter specifications ensure the surfactant achieves both manufacturing feasibility and the complex performance requirements of preventing cissing and maintaining alignment properties.
Solution Approach 2:
The copolymer surfactant structure incorporates different functional groups at different locations within the molecular structure - hydrophilic ether groups for water solubility and coating uniformity, and hydrophobic aromatic/cycloalkane rings for liquid crystal compatibility. This local differentiation of quality within the molecular structure enables the surfactant to perform multiple functions simultaneously.
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 enables the formation of a liquid crystal cured layer with suppressed cissing and excellent alignment properties, leading to improved performance of optical films and image display devices.
Implementation Method 1
a liquid crystal composition comprising a liquid crystal compound and a surfactant... suppressing cissing during formation of a liquid crystal cured layer
Implementation Method 2
the alignment properties of the liquid crystal cured layer to be formed are degraded... excellent alignment properties
Data Source
AI summary
A liquid crystal composition capable of forming a liquid crystal cured layer with suppressed cissing during formation of a liquid crystal cured layer and excellent alignment properties, a liquid crystal cured layer, an optical film, a polarizing plate, and an image display device. The liquid crystal composition includes a liquid crystal compound and a surfactant, in which the surfactant is a copolymer having a repeating unit A including two or more silicon atom-containing groups each having three substituents and a repeating unit B including two or more ring structures consisting of a cycloalkane ring or a monocyclic aromatic ring in which at least one of the ring structures consists of a monocyclic aromatic ring.