Electrochromic Solution Viscosity Control for Coloration Uniformity
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Solution Overview
Problem
Electrochromic self-erasing solutions face issues with coloration segregation and current leakage, leading to non-uniform coloration and high current consumption, which are unacceptable for commercial applications.
Innovation Solution
An electrochromic solution comprising a solvent, a thickening polymer agent with a molecular weight of at least 50,000 g/mol, and an additive with a molecular weight between 300 and 50,000 g/mol, which reduces segregation and current leakage while maintaining a suitable viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thickening polymer agent is added to increase viscosity, then coloration segregation is reduced, but current leakage increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the molecular weight of the polymer (at least 50,000 g/mol) and its concentration (0.1-10% w/v) to achieve optimal viscosity that reduces segregation while limiting current leakage. This quantitative parameter optimization resolves the contradiction between stability and energy loss.
Solution Approach 2:
The patent uses composite materials by combining the thickening polymer agent with specific electrochromic compounds (viologens, phenazines, phenothiazines) and electrolytes in a coordinated solvent system. This composite formulation achieves both reduced segregation and controlled current leakage through synergistic interactions between components.
2Speed
If the electrochromic solution is kept highly mobile for rapid bleaching, then bleaching rate increases, but coloration segregation worsens
Solution Approach 1:
The patent applies parameter changes by optimizing the polymer molecular weight (at least 50,000 g/mol) and concentration to achieve a specific viscosity range that allows sufficient molecular mobility for rapid bleaching while preventing segregation. This balances speed and stability through precise parameter control.
Solution Approach 2:
The patent applies local quality by creating different micro-environments in the solution where the polymer provides localized structural organization to prevent segregation, while maintaining overall solution mobility for rapid bleaching. The polymer creates local cages or microstructures that guide molecular behavior without restricting global diffusion.
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 solution effectively reduces segregation and current leakage, achieving a balance between deep coloration uniformity and rapid bleaching rates, making it suitable for high-quality electrochromic devices such as ophthalmic lenses.
Implementation Method 1
The material undergoes reversible changes in optical properties by oxidation and reduction. Such redox reactions of the compounds provide the 'self-erasing' feature to a device.
Implementation Method 2
Electrochromism is a well-known physical phenomenon which is observed with certain classes of chemical compounds that change reversibly colour when a voltage is applied to them.
Implementation Method 3
The coloration segregation problem emerges from the continuous operation of the electrochromic system... The segregation is thus due to migration and convection of the coloring species which remain adjacent to said electrical elements... a thickening polymer agent having a molecular weight of at least 50,000 g/mol
Implementation Method 4
Yet another problem encountered in electrochromic self-erasing devices relates to current leakage... an additive having a molecular weight between 300 and 50,000 g/mol... which reduces segregation and current leakage
Implementation Method 5
Differences in solubility between the colored and uncolored forms of any of the coloring species may also contribute to segregation. In their colored form, either or both of the coloring species may fully or partially phase separate of the electrochromic solution depending on their solubilities
Data Source
AI summary
The present invention relates to an electrochromic solution and a use thereof, wherein the said solution comprises: a solvent; a thickening polymer agent having a molecular weight of at least 50,000 g/mol, preferably 200,000 g/mol, more preferably of at least 250,000 g/mol; at least an additive having a molecular weight between 300 and 50,000 g/mol, preferably between 320 and 20,000 g/mol; a redox chemical mixture in solution in said solvent said mixture being constituted of at least one electrochromic reducing compound and at least one electrochromic oxidizing compound, and which colors in the presence of an applied voltage and which bleaches to a colorless condition in the absence of an applied voltage. The invention further relates to a device comprising said solution.