Hydrophobic Aerogel Production via Surface Modification
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Solution Overview
Problem
Current methods for producing hydrophobed aerogels are costly, time-consuming, and resource-intensive, requiring high temperatures, large amounts of hazardous chemicals, and multi-step processes, which complicates large-scale industrial implementation and increases waste generation.
Innovation Solution
A process involving the preparation of a sol comprising [SiO4/2] units and [RxSiO(4−x)/2] units, followed by gel formation and surface modification in the presence of a compatibilizer and organosiloxane, using an acid or chlorosilane as an initiator, to produce aerogels without the need for solvent exchange and at reduced temperatures and chemical usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If supercritical drying is used to preserve gel structure, then aerogel quality is improved, but process complexity and cost increase due to high-pressure technology requirements
Solution Approach 1:
The invention changes the chemical parameters of the gel surface by introducing organosiloxane groups through surface modification. This chemical parameter change allows the gel to maintain structural stability during drying at atmospheric pressure, eliminating the need for supercritical drying conditions while preserving aerogel quality.
Solution Approach 2:
The invention introduces an intermediary substance (organosiloxane) that modifies the gel surface properties. This intermediary acts as a protective layer during drying, preventing capillary forces from collapsing the gel structure, thereby enabling simple atmospheric pressure drying while maintaining aerogel integrity.
2Loss of time
If surface modification is performed without solvent exchange, then process time is reduced, but gel structure destruction increases due to hydrolysis-sensitive chemicals reacting with pore liquid
Solution Approach 1:
The invention converts the harmful reaction between hydrolysis-sensitive chemicals and water into a beneficial process. By carefully controlling the surface modification conditions, the reaction between organosiloxane and pore water creates a protective hydrophobic layer that prevents further unwanted reactions and stabilizes the gel structure during drying.
Solution Approach 2:
The invention changes the physical and chemical parameters of the surface modification process, including temperature, organosiloxane concentration, and catalyst selection. These parameter optimizations enable direct surface modification without solvent exchange while preventing gel structure destruction through controlled reaction conditions.
3Object-affected harmful factors
If conventional surface modification methods are used, then hydrophobicity is achieved, but resource consumption and waste generation increase due to multi-step processes and large amounts of chemicals
Solution Approach 1:
The invention merges multiple process steps into a single integrated surface modification step. By combining surface modification with controlled drying in one operation, the process eliminates the need for separate solvent exchange steps and reduces overall chemical consumption while achieving the desired hydrophobicity.
Solution Approach 2:
The invention enables the gel to self-modify its surface properties through controlled reaction with organosiloxane in the presence of a catalyst. This self-service approach reduces the need for extensive external chemical treatments and multiple processing steps, thereby minimizing resource consumption and waste generation.
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 method results in an economical, safe, and efficient production of hydrophobic aerogels with improved reaction rates and reduced processing costs, enabling a continuous large-scale industrial process while minimizing waste and hazardous substance use.
Implementation Method 1
preparing a sol comprising [SiO4/2] units and [RxSiO(4−x)/2] units
Implementation Method 2
forming a gel out of the sol
Implementation Method 3
surface modifying the resultant gel in the presence of above 0.1 wt % of a compatibilizer in a mixture comprising organosiloxane and initiator
Implementation Method 4
Aerogels are highly porous rigid solids in that their volume is up to more than 95% pores... These properties make aerogels ideal materials for applications in thermal insulation
Data Source
AI summary
It is an object of the invention to provide an economically viable process for the production of hydrophobized aerogels which works both inexpensively and in a resource-conserving manner. 2.2. This object is achieved by the provision of a process for producing organically modified aerogels by producing a sol containing [SiO4/2] units and [RxSiO(4−X)/2] a units, where x may be the same or different and is 1, 2 or 3, and R may be the same or different and is hydrogen or an organic substituted or unsubstituted radical, using the sol to form a gel, surface-modifying the gel obtained in the presence of more than 0.1% by weight of a phase modifier in a mixture comprising organosiloxane and initiator, wherein the mixture contains at least 20% by weight of organosiloxane and wherein the initiator consists of acid or organosiloxane or mixtures thereof and the gels obtained are dried. 2.3. The aerogels provided can be used as insulating materials, especially in thermal insulation.