Polymerizable Compound for Low-Temperature Liquid Crystal Orientation
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Solution Overview
Problem
Existing polymerizable compounds with (meth)acrylic groups require high temperatures for polymerization, leading to uneven physical properties and difficulty in fixing the orientation of liquid crystal molecules, which is undesirable for optically anisotropic materials.
Innovation Solution
A polymerizable compound with a linear array of rings terminated by (meth)acrylic groups connected via different spacers, allowing for polymerization at lower temperatures and forming optically anisotropic materials with improved orientation and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polymerization is conducted at high temperatures to cure compounds existing in liquid crystal phase at high temperatures, then the liquid crystal phase stability is improved, but thermal polymerization occurs concurrently causing uneven physical properties and difficulty in fixing orientation
Solution Approach 1:
The patent modifies the molecular structure of liquid crystalline compounds by introducing specific spacer groups and aromatic rings, which changes the phase transition temperature parameter from high temperature to lower temperature range. This allows the liquid crystal phase to remain stable at temperatures where thermal polymerization does not occur concurrently, enabling precise orientation fixation during photo-polymerization.
Solution Approach 2:
The patent performs uniform orientation of liquid crystal molecules before polymerization, and then uses photo-polymerization to semipermanently fix this orientation. By conducting polymerization at lower temperatures where thermal polymerization does not interfere, the preliminary orientation is preserved and fixed with high precision, avoiding the orientation loss that occurs at high temperatures.
2Productivity
If polymerization is conducted at high temperatures, then the curing process is accelerated, but thermal polymerization causes uneven physical properties in cured products
Solution Approach 1:
The patent replaces thermal polymerization with photo-polymerization by introducing polymerizable functional groups that respond to light irradiation. This substitution allows curing to proceed at lower temperatures through photoinitiated polymerization, maintaining high productivity while avoiding the harmful effects of thermal polymerization such as uneven physical properties and orientation loss.
3Temperature
If compounds with high liquid crystal phase temperatures are used, then the liquid crystal phase can be maintained, but temperature control becomes difficult and orientation fixation is problematic
Solution Approach 1:
The patent systematically changes the temperature parameter by designing liquid crystalline compounds with specific molecular structures including spacers and aromatic rings. This structural modification lowers the liquid crystal phase temperature to a range (below the polymerization temperature) that is easier to control, allowing straightforward temperature management during the curing process while maintaining liquid crystal phase characteristics.
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 compound enables the formation of optically anisotropic materials with excellent heat resistance, solvent resistance, and optical properties, suitable for applications like retardation plates and polarization plates, by maintaining orientation and stability at lower temperatures.
Implementation Method 1
photo-polymerizing by irradiation with energy beam such as ultraviolet light while keeping the liquid crystal state to semipermanently fix the is uniform orientation
Data Source
AI summary
The polymerizable compound of the present invention is represented by general formula (1) below and can provide a composition that is polymerizable near ambient temperature and exists in a liquid crystal phase at low temperatures. The composition and a (co)polymer of the polymerizable compound of the present invention are liquid crystal substances useful as optically anisotropic materials.(In the formula, each of rings A1 to A3 represents a benzene ring, cyclohexane ring, etc.; each of X to Z represents a C1-8 alkyl or alkoxy group, C2-6 alkenyl group, halogen atom, cyano group, or CH2═CR3—COO—; each of R1 to R3 represents a hydrogen atom, methyl group, or halogen atom; each of L1 to L3 represents —CH2CH2COO—, —COO—, —OCO—, —CH2CH2—, —O(CH2)f— (herein, f=1-8), etc.; n represents 0 or 1; and a to c represent such numbers that the polymerizable compound has at least one or more of any of X, Y, and Z).