Silica Aerogel Ambient Drying via Surface Modification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing silica aerogels are complex, costly, and inefficient, with difficulties in controlling density and maintaining mechanical properties during ambient drying, leading to unpredictable tap density and increased thermal conductivity due to moisture absorption.
Innovation Solution
A method involving the sequential addition of first and second water glass solutions with specific silicon dioxide concentrations, combined with an acid catalyst and surface modifier, to form a stable silica wet gel structure that is then dried, allowing for simultaneous gelation, solvent exchange, and surface modification, resulting in a silica aerogel with controlled density and enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sol-gel method is used to produce silica aerogel, then the aerogel can be produced with good physical properties, but the production process becomes very complicated and requires much cost and time
Solution Approach 1:
The patent combines multiple steps (sol formation, hydrogel formation, aging, solvent exchange, surface modification, and drying) into a simplified one-step ambient drying process. The key innovation is adding a surface modifier during gelation that simultaneously performs surface hydrophobization and stabilizes the gel structure, eliminating the need for separate solvent exchange and surface modification steps.
Solution Approach 2:
The patent extracts and eliminates the complex solvent exchange step from the traditional sol-gel process. By using a surface modifier that enables direct ambient drying, the time-consuming solvent exchange operation is completely removed from the production process.
2Ease of manufacture
If ambient drying technique is used to ensure price competitiveness, then the production cost is reduced, but the pore structure is shrunk due to high capillary force
Solution Approach 1:
The patent applies surface modification before drying by adding a surface modifier during gelation. This preliminary action creates a hydrophobic surface layer that prevents capillary water from entering pores during drying, thereby preventing pore structure shrinkage before the drying process begins.
Solution Approach 2:
The surface modifier creates a preliminary protective barrier against capillary forces by making the surface hydrophobic. This anti-action prevents the harmful capillary suction that would otherwise cause pore collapse during ambient drying.
3Ease of manufacture
If the silica aerogel absorbs moisture, then the aerogel can be produced easily, but the characteristics and physical properties of gel structure are deteriorated
Solution Approach 1:
The surface modifier enables the aerogel to self-protect against moisture absorption. The hydrophobic surface layer automatically repels water, eliminating the need for additional protective treatments or complex environmental controls during production and storage.
4Reliability
If it is required to permanently prevent moisture absorption, then the aerogel performance is improved, but additional surface modification steps are required
Solution Approach 1:
The patent merges surface modification with the gelation process by adding the surface modifier during gel formation. This combination achieves permanent hydrophobicity without requiring separate surface modification steps after gelation, thereby maintaining process simplicity while ensuring moisture resistance.
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 simplifies the production process, enhances mechanical properties, and allows for precise control of tap density, improving productivity and economical efficiency while maintaining low thermal conductivity and hydrophobicity.
Implementation Method 1
adding a first water glass solution and an acid catalyst to a reactor to form a first silica wet gel
Implementation Method 2
adding a first water glass solution and an acid catalyst to a reactor to form a first silica wet gel
Implementation Method 3
adding a surface modifier solution to the first silica wet gel to form a second silica wet gel
Implementation Method 4
drying a silica wet gel including the first silica wet gel and the second silica wet gel
Data Source
AI summary
The present invention relates to a method for producing a silica aerogel and a silica aerogel produced thereby. More specifically, a first water glass solution is used to form a first silica wet gel, and then a second water glass solution is additionally added to form a second silica wet gel organically bonded to the first silica wet gel which serves as a basic skeleton, so that a silica aerogel with enhanced physical properties is formed to increase the resistance to shrinkage in ambient drying, and the concentration of silicon dioxide in each of the first and second water glass solutions is controlled, thereby providing a method for producing a silica aerogel by which a silica aerogel having a specific tap density and controllable density can be produced, and also providing a silicon aerogel produced by the method.