Polymerizable Liquid Crystal Film Alignment Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing infrared light-reflective films using cholesteric liquid crystals face issues with wind unevenness during drying and poor liquid crystal alignment, leading to surface defects and reduced optical quality.
Innovation Solution
A method involving a polymerizable liquid crystal composition with a specific alignment controlling agent, applied in a controlled amount, is used to coat and dry the film, which suppresses wind unevenness and improves liquid crystal alignment, resulting in a high-quality film with enhanced surface conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a polymerizable liquid crystal composition is coated and dried to form a cholesteric liquid crystal film, then infrared light reflection is achieved, but wind unevenness in drying occurs causing thickness unevenness and surface defects
Solution Approach 1:
A fluorinated alignment controlling agent is introduced as an intermediary substance in the liquid crystal composition. This agent mediates between the liquid crystal molecules and the drying process, reducing surface tension and preventing wind unevenness during drying, thereby achieving uniform film thickness while maintaining infrared reflection performance
Solution Approach 2:
The surface tension parameter of the liquid crystal composition is modified by adding fluorinated compounds. This parameter change prevents capillary waves and wind unevenness during the drying process, resulting in uniform film formation without thickness variations or surface defects
2Stability of the object's composition
If conventional alignment methods are used for cholesteric liquid crystal, then liquid crystal alignment is achieved, but surface defects such as streaks and unevenness occur
Solution Approach 1:
The liquid crystal composition is formulated as a composite material containing fluorinated alignment controlling agents alongside the cholesteric liquid crystal compounds. This composite formulation achieves proper liquid crystal alignment while the fluorinated components prevent surface defects like streaks and unevenness by controlling surface tension and drying behavior
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 method effectively reduces wind unevenness and improves liquid crystal alignment, producing films with superior surface conditions and optical properties suitable for infrared light reflection.
Implementation Method 1
a method of producing a film including: a coating step of coating, on a substrate, a polymerizable liquid crystal composition containing (A) a polymerizable liquid crystal compound... and an irradiation step of irradiating the coated film with actinic radiation to fix the cholesteric liquid crystal phase
Implementation Method 2
light of circularly-polarized light in one direction can be reflected selectively with high efficiency in the region of 700 to 1200 nm by forming one cholesteric liquid crystal phase
Data Source
AI summary
Provided is a method of producing a film including: a coating step of coating, on a substrate, a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound, an alignment controlling agent capable of controlling alignment of the polymerizable liquid crystal compound, a polymerization initiator and coated film a solvent; and a drying step of drying, wherein the alignment controlling agent is a compound represented by formula (1) below, and the alignment controlling agent is added in 0.005 to 0.2 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound:In general formula (1), each of L1 and L2 represents an alkylene group having 1 to 6 carbon atoms that may be substituted with a fluorine atom or the like, and n1 and n2 represents integers of 3 or more.