Aerogel Precursor Hydrophobicity High Temperature Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aerogel synthesis methods face challenges in achieving high temperature hydrophobicity and durability due to the inefficiency of surface hydrophobizing agents and the instability of hydrophobic groups when exposed to heat, leading to reduced thermal insulation and durability.
Innovation Solution
A method involving an aerogel precursor with specific structural units and a hydrolysis and polycondensation process, which imparts hydrophobicity to the wet gel, allowing for improved compatibility with organic solvents and reduced agent usage, and a supercritical drying process without solvent replacement, enhancing high temperature stability and thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface hydrophobizing treatment is performed on wet gel, then room temperature hydrophobicity is improved, but high temperature durability deteriorates due to residual agent oxidation
Solution Approach 1:
The invention incorporates hydrophobic structural units directly into the aerogel precursor before gelation, rather than performing surface modification after gel formation. This preliminary incorporation ensures that hydrophobicity is an intrinsic property of the aerogel structure itself, eliminating the need for post-synthesis surface treatment and avoiding the durability issues caused by residual hydrophobizing agents
Solution Approach 2:
The aerogel precursor is designed to self-hydrophobize through its inherent molecular structure containing hydrophobic groups. The precursor molecules naturally possess hydrophobic characteristics that are maintained throughout the gelation and drying processes, eliminating the need for external hydrophobizing agents and their associated durability problems
2Reliability
If wet gel is used for surface modification, then room temperature hydrophobicity is improved, but reaction efficiency deteriorates due to two-phase liquid/solid structure
Solution Approach 1:
The invention changes the physical state parameter of the precursor from a two-phase wet gel to a homogeneous liquid solution. By maintaining the precursor in a liquid state during hydrophobic group incorporation, the reaction efficiency is dramatically improved while still achieving the desired room temperature hydrophobicity in the final aerogel product
3Reliability
If large amount of surface hydrophobizing agent is used, then room temperature hydrophobicity is improved, but high temperature stability deteriorates due to agent oxidation
Solution Approach 1:
The hydrophobic groups are incorporated into the aerogel structure during the precursor synthesis stage, before gelation occurs. This preliminary incorporation eliminates the need for large amounts of post-synthesis hydrophobizing agents, thereby maintaining high temperature stability while achieving room temperature hydrophobicity
Solution Approach 2:
The invention creates a composite precursor structure combining hydrophilic silica network formers (TEOS, MTMS) with hydrophobic units (MTMS, VMCTS). This composite structure provides both the structural framework and inherent hydrophobicity, eliminating the need for separate hydrophobizing agents that would compromise high temperature stability
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 aerogel precursor achieves excellent room temperature and high temperature hydrophobicity, high temperature stability, and thermal insulation, with improved durability and efficiency in the aerogel production process, maintaining viscosity and hydrophobicity over time.
Implementation Method 1
a hydrolysis and polycondensation process
Implementation Method 2
a hydrolysis and polycondensation process
Implementation Method 3
a supercritical drying process without solvent replacement
Data Source
Figure 1
Figure 2
AI summary
Provided are an aerogel precursor, a method for preparing the same, an aerogel prepared therewith, and a method for preparing an aerogel using the same, wherein the aerogel precursor includes a structural unit represented by Formula 1 below and at least one selected from the group consisting of structural units represented by Formulae 2 to 4 in a molar ratio of 100:1 to 100:20, and has a weight average molecular weight of 1,000 g/mol to 6,000 g/mol, and a viscosity of 2.0 to 4.0 cps after heating for 24 hours or more at 45 to 60°C.