Dibenzothiophene Liquid Crystal Compounds with Flexible Side Chains
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Solution Overview
Problem
Existing liquid crystal compounds with rigid dibenzothiophene rings have high dielectric anisotropy and birefringence but poor solubility and are prone to crystallization at low temperatures, limiting their application in display devices.
Innovation Solution
A new liquid crystal compound is developed with cyclopropyl, cyclopentyl, or 2-tetrahydrofuryl groups as chain end groups, enhancing solubility and stability by incorporating these groups into the dibenzothiophene-class molecules, which improves low-temperature stability and expands application ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid dibenzothiophene ring structure is used in liquid crystal compounds, then dielectric anisotropy and birefringence are improved, but solubility deteriorates and crystallization occurs at low temperatures
Solution Approach 1:
The rigid dibenzothiophene core is segmented by introducing flexible side chains at positions 2 and 6, creating a molecular structure where the rigid core provides optical properties while the flexible chains provide solubility. This segmentation allows independent optimization of different molecular regions for conflicting properties.
Solution Approach 2:
Different regions of the molecule are assigned different properties: the central dibenzothiophene ring provides high dielectric anisotropy and birefringence, while the terminal alkyl or alkoxy groups provide flexibility and solubility. This local differentiation resolves the contradiction between rigid core benefits and overall molecular solubility.
2Reliability
If rigid dibenzothiophene ring structure is used in liquid crystal compounds, then dielectric anisotropy and birefringence are improved, but low-temperature stability deteriorates due to crystallization
Solution Approach 1:
The molecule is divided into a rigid dibenzothiophene core for optical properties and flexible terminal chains for thermal stability. This segmentation prevents crystallization at low temperatures while maintaining high birefringence, extending the liquid crystal phase temperature range.
Solution Approach 2:
By changing the length and type of side chains (alkyl vs alkoxy, different carbon numbers), the patent optimizes the liquid crystal phase stability at low temperatures while preserving the core's optical anisotropy properties. This parameter adjustment resolves the temperature stability issue.
3Reliability
If rigid dibenzothiophene ring structure is used in liquid crystal compounds, then optical anisotropy is improved, but ease of manufacture deteriorates due to poor solubility
Solution Approach 1:
The terminal groups are designed with specific local qualities (alkoxy vs alkyl, different chain lengths) to enhance solubility without affecting the core's optical properties. This local modification makes the compounds easier to handle and process during manufacturing while maintaining high optical anisotropy.
Solution Approach 2:
By adjusting parameters such as side chain length and composition, the patent optimizes both optical performance and manufacturability. The flexible chains improve solubility for easier processing while the rigid core maintains high optical anisotropy, resolving the manufacturing difficulty.
Data Source
Figure 1
AI summary
The present invention discloses a compound of which a structural formula thereof is represented as the following formula I: The compound disclosed by the present invention can be used as a liquid crystal compound and overcomes the problem that solubility of the traditional dibenzothiophene-class liquid crystals is poor, and thus can be better applied to the liquid crystal material field. The present invention further discloses a liquid crystal medium containing the compound and an application thereof.