Polymerizable Liquid Crystal Film for Uniform Multilayer Alignment
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Solution Overview
Problem
Existing methods for preparing multilayer cholesteric polymer films require high temperatures, are material-limited, and suffer from dewetting issues, leading to non-uniform alignment and inhomogeneous thickness, making them unsuitable for mass production and complex.
Innovation Solution
A polymerizable LC material comprising reactive mesogenic compounds and specific alkyl radicals, allowing for UV photopolymerization with improved solubility, broadening potential, and resistance to yellowing, which can be used to create multilayer stacks with enhanced alignment and thickness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperatures are used to achieve uniform alignment in CLC polymer layers, then alignment quality improves, but manufacturing complexity and cost increase, making it unsuitable for mass production
Solution Approach 1:
The patent introduces a new parameter - surface treatment of the substrate with specific energy values (e.g., 50-200 mJ/cm²) - to replace the traditional parameter of high temperature (150°C or above). This parameter change allows achieving uniform alignment at lower temperatures, thus resolving the contradiction between alignment quality and manufacturing complexity
Solution Approach 2:
The patent replaces the thermal field (heating system) with a different physical mechanism - surface treatment energy field. Instead of using heat to achieve alignment, the invention uses controlled surface energy modification to guide molecular orientation, thereby eliminating the need for complex high-temperature manufacturing equipment
2Manufacturing precision
If multiple polymer layers with different glass temperatures are used for multilayer preparation, then alignment during lamination improves, but material selection is severely limited and production becomes more complicated
Solution Approach 1:
The patent makes the surface treatment method universally applicable to different polymer materials regardless of their glass transition temperatures. The same surface treatment principle and energy range can be used for various materials (acrylates, styrenes, methacrylates, etc.), eliminating the need to select materials based on specific temperature requirements and greatly expanding material flexibility
3Manufacturing precision
If surfactants are added to achieve good alignment and coating quality, then film uniformity improves, but dewetting occurs in multilayer applications leading to inhomogeneous thickness
Solution Approach 1:
The patent uses surface treatment as an intermediary mechanism between the substrate and the polymer material. Instead of adding chemical surfactants that cause dewetting, the invention creates a controlled surface energy interface that promotes uniform coating and prevents dewetting, thus maintaining film homogeneity while achieving good alignment
Solution Approach 2:
The patent extracts and removes the problematic component - surfactants - from the formulation. By eliminating surfactants and replacing their function with surface treatment, the invention avoids the dewetting issue that surfactants cause in multilayer applications, thereby maintaining coating uniformity without compromising film stability
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 solution enables the production of multilayer polymer films with high birefringence, favorable transition temperatures, and resistance to UV light, overcoming the limitations of prior methods by providing improved alignment and uniformity without the need for surfactants.
Implementation Method 1
A polymerizable LC material comprising reactive mesogenic compounds and specific alkyl radicals, allowing for UV photopolymerization
Implementation Method 2
multilayer cholesteric polymer films... exhibiting different reflection wavelength
Implementation Method 3
The invention relates to a polymerizable LC material... one or more reactive mesogenic compounds... high birefringence
Data Source
AI summary
A polymerizable LC material comprising one or more reactive mesogenic compounds and one or more compounds of formula I,Furthermore, a method for its preparation, a polymer film obtainable from a corresponding polymerizable LC material, a method of preparation of such polymer film, and the use of such polymer film and said polymerizable LC material in optical, electro-optical, in particular electrooptical devices in the field of augmented or virtual reality.