Aerogel Drying Using Two-Liquid Phase Buoyancy
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Solution Overview
Problem
Conventional methods for producing aerogels result in low productivity and limited size due to brittleness and breakage during the drying process, leading to unsatisfactory yield and size constraints.
Innovation Solution
A novel method involving a drying process where an undried aerogel is placed in a liquid phase system with two solvents, where the first solvent with a lower specific gravity and boiling point than the second solvent is evaporated, allowing the aerogel to float and dry, followed by high-temperature drying to achieve larger, more stable, and transparent aerogel production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional drying methods (supercritical drying, freeze drying, atmospheric pressure drying with solvent exchange) are used, then the aerogel can be obtained without breakage, but the productivity is low and the size of aerogel is limited
Solution Approach 1:
The invention changes the drying parameters by using a two-liquid phase system with different densities and boiling points. The first liquid phase (lower density, lower boiling point) allows for gentle evaporation at lower temperatures, while the second liquid phase (higher density, higher boiling point) provides a stable environment. This parameter change enables larger aerogels to be dried without breakage while improving productivity.
Solution Approach 2:
The first liquid phase acts as an intermediary medium between the aerogel and the second liquid phase. It facilitates gradual solvent removal through evaporation while the aerogel floats on the interface, providing mechanical support and preventing breakage. This intermediary system enables both high integrity and high productivity.
2Ease of operation
If the aerogel is dried at atmospheric pressure with solvent exchange, then the handling difficulty is reduced, but the yield and aerogel size are limited
Solution Approach 1:
The invention uses a two-liquid phase system where the first liquid phase has lower density and lower boiling point than the second liquid phase. This parameter configuration allows the aerogel to float at the interface during drying, making it easy to handle while enabling larger sizes and higher yields that were not achievable with conventional atmospheric pressure drying methods.
3Productivity
If the aerogel size is increased, then the productivity improves, but the aerogel becomes more prone to breakage due to brittleness
Solution Approach 1:
The first liquid phase provides buoyant support to the aerogel during the drying process, counteracting the gravitational force and reducing mechanical stress on the brittle aerogel structure. This allows larger aerogels to be produced with improved strength retention, resolving the contradiction between size and mechanical strength.
Solution Approach 2:
The invention changes the drying environment parameters by using a two-liquid phase system with controlled densities and boiling points. This creates a gentle drying environment that supports large aerogel structures without causing breakage, thereby improving productivity while maintaining mechanical strength.
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 enhances productivity by producing aerogels with increased size and high yield, while minimizing cracking and maintaining transparency, thus overcoming the limitations of conventional drying techniques.
Implementation Method 1
a second step in which a first solvent constituting the first liquid phase is evaporated from the first liquid phase at a first temperature higher than room temperature
Implementation Method 2
the undried aerogel is low-temperature dried until the undried aerogel floats on a liquid surface of the second liquid phase
Data Source
AI summary
An aerogel and drying method, the aerogel having a larger size, good productivity, and high transparency. The aerogel has a silsesquioxane structure and exhibits two exothermic peaks observed in a temperature range of 300 to 600° C. as measured by TG-DTA (thermogravimetry-differential thermal analysis) under an inert gas atmosphere containing 80% by volume of an inert gas and 20% by volume of oxygen. A method for producing aerogel includes a drying step including a first step in which an aerogel which has undergone condensation of a hydrolysate is placed in a liquid phase system having a first liquid phase and a second liquid phase; a second step in which a first solvent constituting the first liquid phase is evaporated from the first liquid phase at a temperature greater than room temperature; and a third step in which heating is still continued after the first liquid phase is evaporated off.