Polymetalloxane Film Stability via Bifunctional Silane Side Chains
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Solution Overview
Problem
Existing methods for forming metal oxide films, such as chemical vapor deposition (CVD), face challenges in achieving industrially usable film thickness and stability due to aggregation issues during hydrolysis of metal alkoxides, particularly when multiple metals are involved, leading to instability and insolubility in organic solvents.
Innovation Solution
A polymetalloxane with structural units represented by general formulae (1-1) and (1-2), containing two or more metals like Al, Ti, Zr, and others, is developed, which includes a trialkylsiloxy group side chain to maintain stability and solubility, allowing for the formation of high-molecular-weight films with enhanced refractive index and crack resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a monofunctional silane compound such as trimethylsilane is introduced into a side chain of a metal molecule of a polymetalloxane to enable stable presence in solution, then the polymetalloxane can be present stably in a transparent and uniform state in a solution, but when the polymetalloxane contains two or more kinds of metals, the metals facilitate the elimination of the trialkylsilanol during hydrolysis reaction, causing aggregation and making it difficult to perform polycondensation stably
Solution Approach 1:
The patent changes the chemical structure parameter by introducing a bifunctional silane compound with two different groups (L1 and L2) attached to the silicon atom. This structural modification allows the silane to provide both solubility enhancement through one group and stable polycondensation capability through the other group, resolving the contradiction between solution stability and polycondensation reliability when multiple metals are present.
Solution Approach 2:
The patent creates a composite side chain structure where a bifunctional silane compound combines multiple functional groups (triaalkylsiloxy group for solubility and other groups for stable polycondensation) in a single molecular unit. This composite structure simultaneously addresses both the solubility requirement and the stable polycondensation requirement even when multiple metal atoms are present in the polymetalloxane.
2Reliability
If a gas-phase process such as chemical vapor deposition is used to form a film of titanium oxide or zirconium oxide, then a film with high heat resistance, high transparency, and high refractive index can be obtained, but the film forming rate is low and it is difficult to obtain an industrially usable film thickness
Solution Approach 1:
The patent replaces the gas-phase physical vapor deposition process with a solution-based chemical process. The polymetalloxane is dissolved in an organic solvent to form a uniform solution that can be applied and cured to form the film. This substitution of the processing mechanism dramatically increases the film forming rate while maintaining the desired film properties of high heat resistance, transparency, and refractive index.
Solution Approach 2:
The patent changes the processing parameters from gas-phase deposition conditions to solution-based chemical reaction conditions. By using a dissolved polymetalloxane solution with controlled composition and curing conditions, the process achieves both high productivity and high film quality, transforming the low-efficiency physical deposition into an efficient chemical transformation process.
3Reliability
If hydrolysis of metal alkoxide is performed to yield polymetalloxane, then a thin film with high transparency and high refractive index can be obtained, but the resulting hydrolysates aggregate and become prone to be insoluble in organic solvent
Solution Approach 1:
The patent introduces a bifunctional silane compound as an intermediary substance that mediates between the hydrolysate and the organic solvent. The silane compound's trialkylsiloxy group provides strong interaction with the hydrolysate to prevent aggregation, while its other groups maintain compatibility with the organic solvent, thus enabling stable dissolution of the polymetalloxane without aggregation.
Solution Approach 2:
The patent creates a composite molecular structure by attaching the bifunctional silane compound to the metal molecule during or after hydrolysis. This composite structure combines the hydrophilic character of the metal oxide core with the hydrophobic character of the silane side chain, resulting in a material that is both insoluble in water (maintaining film integrity) and soluble in organic solvents (enabling processing).
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 polymetalloxane solution enables the production of transparent, high-molecular-weight films with improved refractive index and crack resistance, facilitating industrial-scale production and application in electronic components and fibers.
Implementation Method 1
a method in which a metal alkoxide is hydrolyzed in a solvent, and the resulting hydrolysates are polycondensed to yield a polymetalloxane
Implementation Method 2
the resulting hydrolysates are polycondensed to yield a polymetalloxane
Implementation Method 3
a monofunctional silane compound such as trimethylsilane, is introduced into a side chain of a metal molecule of a polymetalloxane to enable the polymetalloxane to be present stably in a transparent and uniform state in a solution
Implementation Method 4
a film composed of a metal oxide has properties such as a high heat resistance, a high transparency, a high refractive index
Data Source
AI summary
A polymetalloxane including structural units represented by formulae (1-1) and (1-2), and having a weight-average molecular weight of 30,000 or more and 2,000,000 or less;wherein, M1 and M2 independently represent different metal atoms; L1 and L2 are each independently a group selected from the group consisting of an allyloxy group, an aryloxy group, and a trialkylsiloxy group; L1 and L2 may be the same or different, and at least one thereof is an allyloxy group or an aryloxy group; R1 and R2 are each independently a hydrogen atom, a C1-12 alkyl group, or a group having a metalloxane bond; m is an integer that represents the valence of the metal atom M1, and a is an integer of 1 to (m−2); and n is an integer that represents the valence of the metal atom M2, and b is an integer of 1 to (n−2).