Polymerizable Liquid Crystal Film Thermal Stability
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Solution Overview
Problem
Current polymerizable liquid crystal materials suffer from low thermal and UV stability, limited transparency to visible light, and require additional additives, making them unsuitable for high-temperature applications and mass production of uniform aligned polymer films.
Innovation Solution
A polymerizable LC material comprising di- or multireactive mesogenic compounds and specific compounds of formula UVI, which enhances thermal and UV stability, transparency, and adhesion to substrates, allowing for the production of polymer films with improved durability and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymerizable liquid crystal materials are used, then the material can be processed and polymerized, but the resulting polymer film exhibits low thermal stability and UV stability, leading to degradation at high temperatures
Solution Approach 1:
The patent introduces compounds of formula UVI as intermediary substances that act as both polymerizable monomers and antioxidants. These compounds mediate between the polymerization process and thermal protection, containing radical-scavenging antioxidant structures (phenolic or aminic groups) that protect the polymer network from thermo-oxidative degradation while participating in the polymerization to form the polymer film itself
Solution Approach 2:
The patent creates a composite polymerizable liquid crystal material by combining di- or multireactive mesogenic compounds with compounds of formula UVI that possess both polymerizable groups and antioxidant functionality. This composite approach integrates multiple functions (polymerization, liquid crystallinity, and antioxidant protection) into a single material system, eliminating the need for separate antioxidant additives
2Stability of the object's composition
If conventional polymerizable liquid crystal materials are used, then polymerization can proceed, but the optical properties such as dispersion and retardance decrease over time due to polymer shrinkage and degradation
Solution Approach 1:
The compounds of formula UVI act as intermediaries that stabilize the polymer network structure during and after polymerization. The antioxidant groups in these compounds prevent chain scission and crosslinking degradation, thereby maintaining the polymer network integrity and preventing polymer shrinkage that would otherwise cause optical property degradation over time
Solution Approach 2:
The patent modifies the chemical composition parameters of the polymerizable liquid crystal material by incorporating compounds with specific functional groups (phenolic or aminic antioxidant groups) at controlled concentrations (0.01-5 wt%). This parameter change transforms the material's resistance to thermal and UV degradation, thereby extending service life while maintaining optical stability
3Reliability
If additional antioxidant additives are used to improve thermal stability, then thermal degradation is reduced, but the material requires further additives increasing complexity and the application bandwidth is limited
Solution Approach 1:
The compounds of formula UVI exhibit multi-functionality by simultaneously serving as polymerizable monomers, liquid crystal components, and antioxidants. This universal functionality eliminates the need for separate antioxidant additives, simplifying the material composition while maintaining thermal stability and broadening the application bandwidth
4Illumination intensity
If conventional polymerizable liquid crystal materials are used, then films can be produced, but the transparency to VIS-light is limited and yellow colouration increases over time
Solution Approach 1:
The compounds of formula UVI act as intermediaries that protect the polymer network from UV-induced degradation and yellowing. The antioxidant groups in these compounds scavenge free radicals generated by UV exposure, preventing the formation of chromophoric degradation products that cause yellowing, thereby maintaining VIS-light transparency over time
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 proposed material achieves high thermal and UV stability, maintains transparency, and ensures favorable adhesion to substrates, enabling the production of polymer films suitable for diverse applications, including optical and electro-optical devices, with improved durability and optical properties.
Implementation Method 1
one or more compounds of formula UVI
Implementation Method 2
polymerizing the mixture
Data Source
AI summary
The invention relates to a polymerisable LC material comprising one or more di- or multireactive mesogenic compounds and one or more compounds of formula UVI,wherein the individual radicals have one of the meaning as given in the claims. Furthermore, the present invention relates also to a method for its preparation, a polymer film with improved thermal durability and UV stability obtainable from a corresponding polymerisable LC material, to a method of preparation of such polymer film, and to the use of such polymer film and said polymerisable LC material for optical, electro-optical, decorative or security devices.