Non-linear Side Chain Liquid Crystal Polyorganosiloxanes for Balanced Electro-Optic Response
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Solution Overview
Problem
Electro-optic (EO) devices with side chain liquid crystal polysiloxanes (SCLCP) suffer from imbalanced response times for transitions between transmitting and scattering states, leading to complex drive schemes and poor aesthetic appearance, particularly in larger devices like smart windows, due to differing switching mechanisms and low nucleation density.
Innovation Solution
A non-linear side chain liquid crystal polyorganosiloxane with specific molecular formulae and structure is developed, comprising units of (R12R2SiO1/2)a(R1R2SiO2/2)b(R1SiO3/2)c(SiO4/2)d(R12SiO2/2)e(R″R2SiO2/2)f, which balances EO response times when used in silicone liquid crystal compositions for EO applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear SCLCP is used in SmA compositions, then the device can achieve transmitting and scattering states, but the EO response times become imbalanced with slower switching to scattering state
Solution Approach 1:
The patent changes the molecular structure parameter of the SCLCP from linear to non-linear (branched) configuration. This structural parameter change fundamentally alters the switching mechanism and kinetics, enabling balanced EO response times for both transmitting and scattering state transitions without requiring complex drive schemes.
Solution Approach 2:
The invention creates a composite liquid crystal composition containing the non-linear SCLCP combined with specific SmA liquid crystal materials. This composite formulation synergistically combines the fast switching characteristics of non-linear SCLCP with the desirable optical properties of SmA phases, achieving balanced response times and homogeneous transitions.
2Reliability
If additives are included to create defects in SmA layers, then nucleation density may increase, but the additives have not proven sufficiently effective in achieving homogeneous transitions
Solution Approach 1:
The patent extracts and eliminates the need for separate defect-inducing additives by incorporating the non-linear SCLCP directly into the liquid crystal composition. The non-linear structure itself inherently provides the necessary nucleation sites and defect structures, simplifying the composition while achieving homogeneous transitions without additional complexity.
3Productivity
If the device gap is small, then the device can be more compact, but the switching to scattering state becomes significantly slower
Solution Approach 1:
The patent changes the molecular architecture parameter from linear to non-linear SCLCP, which fundamentally alters the switching mechanism. This enables small gap devices to achieve fast switching to scattering state through a different physical mechanism that is not constrained by the gap size limitation affecting linear SCLCP devices.
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 non-linear SCLCP composition achieves balanced EO response times, improving the aesthetic and efficiency of EO devices by ensuring homogeneous transitions without compromising the clarity of the clear state, thus addressing the imbalanced response issues in existing SCLCP compositions.
Implementation Method 1
Side Chain Liquid Crystal Polysiloxanes with non-linear side chains exhibit balanced electro-optic responses and can be used in electro-optic devices
Implementation Method 2
The non-linear SCLCP may be used in a silicone liquid crystal composition for electro-optic applications and devices
Data Source
AI summary
A non-linear side chain liquid crystal polyorganosiloxane differs from previous side chain liquid crystal polyorganosiloxanes. A method for preparing the non-linear side chain liquid crystal polyorganosiloxane involves hydrosilylation reaction of a SiH rich intermediate with an aliphatically unsaturated mesogenic compound. A liquid crystal composition containing the non-linear side chain liquid crystal polyorganosiloxane is useful in dynamic scattering mode electro-optic device for various applications.