Aerogel Production via Mixed Silane Ratios
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Solution Overview
Problem
Conventional aerogels face challenges in achieving low density and large area production with excellent thermal insulating characteristics due to high density and limited size, along with defects like cracks and voids, which hinder their mass production and application potential.
Innovation Solution
A method involving the mixing of tetra-functional, tri-functional, and di-functional silane compounds at specific ratios to form a sol, followed by a non-supercritical drying process, results in an aerogel with a density of 0.15 g/cm³ or less and a large area of 400 cm² or more, minimizing defects and enhancing thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aerogel drying methods are used, then thermal insulating characteristics are excellent, but the gel shrinks and develops defects such as cracks and voids
Solution Approach 1:
The invention changes the chemical composition parameters of the silane compound mixture (specifically using a molar ratio of tetra-functional to tri-functional silane compounds between 1:4 and 1:1) to modify the gel structure and reduce capillary forces during drying, thereby preventing defects while maintaining thermal insulation properties
Solution Approach 2:
The invention uses a composite silane compound system combining tetra-functional silane compounds (such as tetramethoxysilane) and tri-functional silane compounds (such as methyltrimethoxysilane) to create a gel structure that balances mechanical strength and pore structure, reducing shrinkage and defects during drying
2Manufacturing precision
If supercritical drying method is used to reduce capillary forces, then defects are reduced, but facility size and production costs increase remarkably
Solution Approach 1:
The invention replaces expensive supercritical drying facilities with simple atmospheric pressure drying equipment by using a chemically modified gel composition that can withstand conventional drying conditions, dramatically reducing facility investment and operational costs
Solution Approach 2:
The invention modifies the chemical parameters of the gel precursor (silane compound composition) to change the physical behavior during drying, enabling the gel to maintain its structure under atmospheric pressure drying conditions without requiring supercritical equipment
3Ease of manufacture
If only tri-functional silane compound is used, then sol formation is simple, but aerogel has cracks and voids and limited area production
Solution Approach 1:
The invention combines tetra-functional silane compounds and tri-functional silane compounds in specific proportions to create a composite precursor system that maintains ease of sol formation while producing a more robust gel structure free from cracks and voids
Solution Approach 2:
The invention introduces tetra-functional silane compounds at specific locations in the molecular network (creating Q4 units alongside Q3 units) to locally reinforce the gel structure where needed, preventing defect formation without complicating the overall manufacturing process
4Strength
If aerogel density is increased, then structural strength improves, but thermal conductivity increases and insulating characteristics deteriorate
Solution Approach 1:
The invention uses a composite silane system that creates a hierarchical pore structure with both small pores (for strength) and interconnected voids (for insulation), achieving a balance between structural integrity and thermal insulation performance
Solution Approach 2:
The invention optimizes the pore structure by using mixed silane compounds to create a controlled porous network that maintains low density (0.15-0.25 g/cm³) while providing sufficient mechanical strength through the tetra-functional crosslinking points
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 approach enables the production of aerogels with improved thermal insulating characteristics and larger areas, overcoming the limitations of previous methods by reducing density and defects, thus facilitating mass production and broader application.
Implementation Method 1
forming a sol by adding a silicon compound to an aqueous solution containing an acid catalyst and hydrolyzing the silicon compound
Implementation Method 2
a drying method in which a gel is dried under a temperature and a pressure below a critical point of a solvent
Implementation Method 3
the gel shrinks due to capillary forces, and this shrinkage force causes various defects such as self-destruction of the entire gel
Data Source
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AI summary
The production method for an aerogel according to the present invention comprises a sol generation step for generating a sol by adding a silicon compound to an aqueous solution containing an acid catalyst and performing hydrolysis, wherein the silicon compound contains at least a quadri-functional silane compound and a tri-functional silane compound among quadri-functional silane compounds, tri-functional silane compounds, and di-functional silane compounds, the density of the aerogel is 0.15 g/cm3 or less, and more preferably, the silicon compound is a mixture of a quadri-functional silane compound, a tri-functional silane compound, and a di-functional silane compound having portions satisfying 0 < Qx < 50, 50 ≤ Tx < 100, 0 ≤ Dx < 30, and Qx + Tx + Dx = 100, where Qx, Tx, and Dx represent the mass percentages of the quadri-functional silane compound, the tri-functional silane compound, and the di-functional silane compound, respectively. The present invention provides a sheet-like or film-like aerogel having excellent thermal insulating characteristics and a large area (e.g., 400 cm2 or more).