Sol Liquid Dispersion Stability via Acid-Dispersant System
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Solution Overview
Problem
The sol-gel method for forming metal oxide thin films faces challenges with dispersion stability, especially when water is present, leading to aggregation and gelation, which complicates the formation of uniform composite inorganic oxide films.
Innovation Solution
A sol liquid containing a metal alkoxide condensate, an α-substituted β-diketone, a water-soluble organic solvent, an inorganic acid, and an organic acid is used, which stabilizes the dispersion even when water is added, allowing for the formation of uniform composite inorganic oxide films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If water is added to the organosol liquid to improve coating performance, then coating property is improved, but dispersion stability deteriorates leading to aggregation and gelation
Solution Approach 1:
The patent introduces a specific dispersant system comprising a carboxylic acid (0.01-5 wt%) and a polyol (0.01-5 wt%) as intermediary substances that mediate between the inorganic particle condensates and the aqueous-organic mixed solvent. This dispersant system prevents direct aggregation between particles when water is added, enabling both good coating property and long-term dispersion stability.
Solution Approach 2:
The patent controls the pH of the sol liquid within a specific range (2-7) by adjusting the ratio and amounts of carboxylic acid and polyol components. This parameter control prevents excessive gelation while maintaining particle dispersion stability, allowing the system to accommodate water addition without losing stability.
2Stability of the object's composition
If a dispersant is added to improve long-term storage stability, then dispersion stability is improved, but the dispersant may remain after baking causing contamination
Solution Approach 1:
The patent employs small molecules (carboxylic acid and polyol) as dispersants that can be completely removed during the baking process. These low molecular weight dispersants volatilize or decompose at baking temperatures, leaving no harmful residues on the final coating, unlike conventional high molecular weight dispersants.
Solution Approach 2:
The patent carefully selects and controls the molecular weight, functional groups, and concentration of the dispersant components to ensure they provide sufficient steric and electrostatic stabilization during storage, yet are completely removable during thermal processing. The carboxylic acid-polyol system achieves this balance through controlled molecular structure.
3Adaptability or versatility
If the sol liquid is made more hydrophilic to allow water mixing, then adaptability is improved, but aggregation between condensates occurs
Solution Approach 1:
The patent creates a composite solvent system combining organic solvents (alcohols, esters, or ethers) with water in specific ratios. This composite solvent system maintains appropriate hydrophobic-hydrophilic balance, allowing mixability with aqueous sols while preventing particle aggregation through the simultaneous presence of organic and aqueous phases.
Solution Approach 2:
The carboxylic acid and polyol dispersants act as intermediaries that bridge the hydrophobic inorganic particle surfaces and the hydrophilic aqueous environment. These dispersants have both hydrophobic interaction capability with particles and hydrophilic interaction with water, enabling stable dispersion in mixed solvent systems.
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
This approach ensures excellent dispersion stability and enables the production of uniform composite inorganic oxide films with good coating properties, even when mixed with aqueous sol liquids at various ratios.
Implementation Method 1
a colloid liquid is produced by hydrolysis with water and a polycondensation reaction using a metal alkoxide or a metal chloride as a raw material
Implementation Method 2
a colloid liquid is produced by hydrolysis with water and a polycondensation reaction using a metal alkoxide or a metal chloride as a raw material
Implementation Method 3
a sol liquid including: a metal alkoxide condensate; an α-substituted β-diketone; and a water-soluble organic solvent, the sol liquid further including an inorganic acid and an organic acid
Data Source
AI summary
Provided is a sol liquid which is excellent in dispersion stability even when the sol liquid contains water, which can be mixed with an existing aqueous sol liquid at any ratio, and which can easily produce even a uniform composite inorganic oxide film with a satisfactory coating property. Specifically, provided is a sol liquid including a metal alkoxide condensate, an α-substituted β-diketone, and a water-soluble organic solvent, the sol liquid further including an inorganic acid and an organic acid.