Polymerizable Liquid Crystal Compound for Phase Difference Film Solubility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing polymerizable liquid crystal compounds have low solubility in organic solvents like methyl ethyl ketone (MEK), leading to poor coating properties and instability of optical characteristics in phase difference films, which affects the retention of necessary optical features in liquid crystal displays.
Innovation Solution
A polymerizable liquid crystal compound with a specific structure, including branched and straight chain alkylene groups and a mesogenic group, enhances solubility in MEK and stabilizes orientation, allowing for improved surface properties and heat resistance in phase difference films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight chain alkylene groups are used in spacer parts of liquid crystal monomers, then the structure is simple and easy to manufacture, but solubility in organic solvents like MEK is low
Solution Approach 1:
The patent applies asymmetry by combining a straight chain alkylene group with a branched alkylene group in the spacer parts of the liquid crystal monomer. This asymmetric structure improves solubility in MEK while maintaining manufacturing feasibility, resolving the contradiction between structural simplicity and solubility reliability.
Solution Approach 2:
The patent introduces local quality by adding a methyl group to the benzene ring of the mesogen part. This localized structural modification specifically enhances solubility in the spacer region without compromising the overall molecular structure or manufacturing process.
2Manufacturing precision
If liquid crystal concentration is increased to improve coating surface properties, then coating quality improves, but viscosity increases making continuous coating difficult
Solution Approach 1:
The patent changes the chemical structure parameters of the liquid crystal monomer by introducing a branched alkylene group, which modifies the solution's physical properties. This structural parameter change allows for higher liquid crystal concentration in the coating solution without excessive viscosity increase, enabling continuous coating with improved surface quality.
3Reliability
If methyl group is introduced to increase solubility, then solubility in MEK improves, but orientation stability after heating deteriorates
Solution Approach 1:
The patent uses asymmetry by combining straight and branched alkylene groups in the spacer, which provides solubility enhancement without the orientation stability issues associated with methyl group substitution on the benzene ring. The asymmetric spacer structure maintains molecular alignment stability while improving solubility.
Solution Approach 2:
The patent applies local quality by placing the branched alkylene group specifically in the spacer region rather than on the mesogen's benzene ring. This localized structural modification achieves solubility improvement in the desired region without affecting the orientation stability of the liquid crystal phase.
4Reliability
If branched alkylene group is introduced to improve solubility, then solubility in MEK increases, but molecular packing efficiency decreases
Solution Approach 1:
The patent applies local quality by confining the branched alkylene structure to the spacer region of the molecule. This localized branching improves solubility in MEK while limiting the impact on overall molecular packing, as the mesogen and core structure remain intact for efficient stacking.
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 achieves high solubility in MEK, stabilizes orientation, and maintains optical characteristics, resulting in phase difference films with enhanced heat resistance and surface properties for liquid crystal displays.
Implementation Method 1
the polymerizable liquid crystal compound, excellent in solubility in an organic solvent such as methyl ethyl ketone (MEK), and a phase difference film and a liquid crystal display using the same
Data Source
AI summary
A polymerizable liquid crystal compound is represented by the following formula (1):P-Sp1-L1-M1-L2-Sp2-Ox (1)wherein P represents a polymerizable group; one of Sp1 and Sp2 represents a branched alkylene group, or an alkylene group containing, in the chain thereof, at least one divalent linking group selected from the group consisting of —O—, —C≡C— and —S—; the other of Sp1 and Sp2 represents a straight chain alkylene group; each of L1 and L2 independently represents a divalent linking group; M1 represents a mesogenic group; and Ox represents a substituent containing an oxetanyl group.