Nanoporous Silicate Sol-Gel Pore Size Control
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Solution Overview
Problem
Current methods for synthesizing monolithic nanoporous silicate materials require structuring agents to control pore size, which involves the use of organic solvents or high temperatures, limiting the ability to produce materials with a wide range of pore sizes and making it difficult to achieve standard emissivity materials for VOC emission studies.
Innovation Solution
A process for synthesizing monolithic nanoporous silicate sol-gel materials without structuring agents, where the pore size distribution is modified by varying the drying protocol, including relative humidity and temperature, to produce materials with controlled porosity for reproducible VOC emission rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If structuring agents are used to control pore size, then pore size control is improved, but device complexity and process difficulty increase
Solution Approach 1:
The patent removes structuring agents from the synthesis process entirely. Instead of using surfactants or templates to control pore size, the invention uses purely physical drying parameters (temperature, humidity, drying rate) to control pore formation, thereby eliminating the complexity associated with structuring agent addition, removal, and optimization.
Solution Approach 2:
The gel matrix itself serves as the pore-structuring element through its own drying behavior. The self-organization of pores is achieved through the gel's inherent properties and the drying conditions, without requiring external structuring agents. The system uses its own structure to define the pore architecture.
2Manufacturing precision
If structuring agents are used to control pore size, then pore size control is improved, but loss of substance and environmental impact increase
Solution Approach 1:
The patent eliminates the need for organic solvents and structuring agents by using aqueous gel systems that dry to form porous structures. This removes the harmful environmental impact and substance loss associated with organic solvent evaporation and structuring agent removal.
Solution Approach 2:
The invention changes the fundamental parameters of the drying process (temperature, relative humidity, drying rate) to control pore size instead of relying on chemically active structuring agents. This parameter-based control achieves the same pore size regulation without the harmful effects of organic solvent and structuring agent loss.
3Manufacturing precision
If high temperatures are used to remove structuring agents, then pore structure is improved, but energy consumption increases
Solution Approach 1:
The patent removes the need for high-temperature treatment by eliminating structuring agents that would require thermal removal. The porous structure is formed directly during the drying process at ambient or moderate temperatures, significantly reducing thermal energy consumption.
Solution Approach 2:
The invention uses controlled drying parameters (temperature, humidity, drying rate) to form the porous structure without requiring high-temperature calcination. This parameter-based approach achieves the desired pore structure at much lower energy input compared to thermal removal of structuring agents.
4Ease of manufacture
If conventional drying methods are used, then production simplicity is maintained, but pore size control capability is limited
Solution Approach 1:
The patent demonstrates that pore size control can be achieved through systematic variation of drying parameters (temperature, relative humidity, drying rate) while maintaining the simplicity of the gel synthesis process. This allows precise pore size control without complicating the manufacturing process.
Solution Approach 2:
The invention uses dynamic control of drying conditions (adjusting temperature, humidity, and drying rate during the process) to achieve precise pore size control. This dynamic approach allows flexibility in pore size regulation while keeping the overall process simple and straightforward.
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
Enables the production of standard and reference emissivity materials that can emit VOCs at predetermined rates, facilitating the validation of emission measurement methods and comparison of different measurement techniques.
Implementation Method 1
drying the gel obtained in step a) in a stream of gas in a drying chamber
Implementation Method 2
synthesizing a gel from at least one organosilyl precursor
Implementation Method 3
synthesizing a gel from at least one organosilyl precursor
Data Source
AI summary
A method for preparing a monolithic nanoporous silicate sol-gel material for modulating the pore size distribution for one single starting composition without the addition of a structuring agent. The method includes the following steps: a) synthesising a gel from at least one organosilylated precursor, the synthesis being carried out in an aqueous medium, optionally including an organic solvent and without a structuring agent, and b) drying the gel obtained in step a) at a temperature between 10° C. and 70° C., preferably between 15° C. and 55° C. and more preferably between 20° C. and 40° C., in a gas flow in a drying chamber to obtain a monolithic nanoporous silicate sol-gel material and a residual relative humidity in the drying chamber of between 0.1 and 20%, preferably between 0.5 and 10% and more preferably about 5%.