MS-51/MTES Hydrophobic Silica Aerogel Processing for High Transmission
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Solution Overview
Problem
Silica aerogels have not achieved the optimal combination of mechanical, thermal, and optical properties for window applications, particularly lacking moisture resistance, high visible transmission, and low haze, with existing methods often compromising these properties through the use of hydrophobic agents and excessive processing.
Innovation Solution
A method involving specific molar ratios and controlled amounts of methyl silicate (MS-51) and methyltriethoxysilane (MTES) in the synthesis of hydrophobic silica wet gel, followed by solvent exchange and aging, to produce hydrophobic silica aerogel with enhanced properties, including densities between 100-200 mg/cc, visible transmission of at least 97.8%, and haze value of 3% or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophobic agents are used to make silica aerogel hydrophobic, then moisture resistance is improved, but visible transmission decreases and haze increases
Solution Approach 1:
The patent changes the chemical parameters of the hydrophobic treatment by using a specific molar ratio of precursors (MS-51 to MTES between 1:1.82 and 1:1) and controlling the amount of hydrophobic agent (0.5-5 mmol per gram of dry gel). This optimized parameter range achieves hydrophobicity while minimizing the negative optical effects that occur with higher concentrations of hydrophobic agents.
Solution Approach 2:
The patent applies partial action by using a controlled, limited amount of hydrophobic agent rather than excessive amounts. The specific range of 0.5-5 mmol per gram of dry gel provides sufficient hydrophobicity while avoiding the threshold where optical properties deteriorate, thus achieving the desired effect without over-treatment.
2Manufacturing precision
If surfactants are added to control particle size in silica wet gel, then particle size control is improved, but processing complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for expensive surfactants by using a simplified precursor system. The controlled hydrolysis and condensation of MS-51 and MTES in the presence of ammonium hydroxide directly produces the desired particle size distribution without requiring additional surfactant additives, thus removing the complex processing steps needed to remove surfactants later.
Solution Approach 2:
The patent implements self-service by allowing the precursor molecules themselves to control particle size through their inherent chemical properties and controlled hydrolysis rates. The ammonium hydroxide catalyst and controlled molar ratios enable the system to self-regulate particle formation without external surfactant intervention, simplifying the overall process.
3Quantity of substance
If excessive solvent baths are used to remove surfactants and hydrophobic agents, then purity is improved, but processing time and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for excessive solvent baths by designing a process that doesn't require surfactant removal. Since surfactants are not used in the first place, the time-consuming multiple solvent exchange steps are eliminated, reducing processing time while maintaining purity through the controlled precipitation and washing steps.
Solution Approach 2:
The patent implements continuous useful action by performing the hydrophobic treatment and particle formation in a single integrated process rather than through multiple sequential steps. The controlled hydrolysis and condensation occur continuously in the presence of ammonium hydroxide, followed by direct filtration and drying, eliminating the need for repeated solvent baths and maintaining continuous productive action throughout the process.
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 produces hydrophobic silica aerogel with exceptional mechanical, thermal, and optical properties, suitable for window applications, without the need for expensive processing steps, maintaining high visible transmission and low haze while resisting moisture.
Implementation Method 1
mixing the first solution and the second solution together to form a mixed solution; allowing components in the mixed solution to react to form silica wet gel
Implementation Method 2
allowing components in the mixed solution to react to form silica wet gel
Implementation Method 3
subjecting the silica wet gel to the solvent exchange solution to form a hydrophobic silica wet gel
Implementation Method 4
drying the hydrophobic silica wet gel to form hydrophobic silica aerogel
Implementation Method 5
producing hydrophobic silica aerogel; the resulting aerogel was characterized by lower visible transmission
Data Source
AI summary
The invention provides hydrophobic silica wet gel, hydrophobic silica aerogel, and methods that can be used to form an enhanced hydrophobic silica aerogel sheet having an advantageous combination of properties. Some embodiments of the invention provide a hydrophobic silica aerogel having advantageous properties, such as desirable performance on visible transmission, haze, or both.