Hydrophilic-Hydrophobic Aerogel Particle Surface Modification
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Solution Overview
Problem
Aerogels are almost completely hydrophobic, making it difficult to control the depth of organics removal and limiting their use in applications that require interaction with aqueous solutions, due to their poor wetting properties and inability to mix well with water.
Innovation Solution
Creating particles with both hydrophobic and hydrophilic regions by subjecting aerogel or similar particles to photocalcination, inverse fluidization in ozonated water or UV light, or alkaline solution treatment, followed by silane treatment to control the depth of organics removal and enhance wetting properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If aerogel particles are made hydrophobic to maintain porosity and inherent properties, then porosity and aerogel properties are maintained, but wetting by water and mixing with aqueous solutions deteriorates
Solution Approach 1:
The aerogel particle is modified to have different surface properties in different regions. The outer surface is made hydrophilic through photocalcination or alkaline treatment, while the inner core retains hydrophobicity. This local differentiation allows the particle to be wetted by water through the hydrophilic outer layer while maintaining the hydrophobic inner structure that provides porosity and aerogel properties.
2Stability of the object's composition
If aerogel particles are made hydrophobic to maintain inherent properties, then aerogel properties are maintained, but mixing with aqueous solutions deteriorates
Solution Approach 1:
The aerogel particle is modified to have different surface properties in different regions. The outer surface is made hydrophilic through photocalcination or alkaline treatment, while the inner core retains hydrophobicity. This local differentiation allows the particle to be wetted by water through the hydrophilic outer layer while maintaining the hydrophobic inner structure that provides porosity and aerogel properties.
3Ease of operation
If photocalcination is used to create hydrophilic regions, then wetting properties improve, but control of organics removal depth becomes challenging
Solution Approach 1:
The photocalcination process incorporates feedback control mechanisms. Treatment time, UV intensity, and particle exposure are monitored and adjusted to achieve the desired depth of organics removal. The process can be staged, with initial treatment followed by evaluation and adjustment of parameters for subsequent treatment cycles, ensuring precise control over the hydrophilic layer depth while maintaining good wetting properties.
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 resulting particles can be easily wetted by water, maintain substantial porosity, and expand their application range, including thermal insulation and moisture-resistant uses, while retaining inherent aerogel properties.
Implementation Method 1
subjecting a particle selected from an aerogel, carbon black, a metal oxide and silica having hydrophobic organic groups on a surface of said particle to photocalcination to remove at least a portion of said hydrophobic organic groups on said surface
Implementation Method 2
subjecting a particle selected from an aerogel, carbon black, a metal oxide and silica having hydrophobic organic groups on a surface of said particle to inverse fluidization in (1) ozonated water
Implementation Method 3
A UV/Ozone photocalciner can be used to subject a hydrophobic particle, such as an aerogel, to a photocalcination process where ozone and free oxygen radicals are generated from the action of UV light on oxygen molecules in the air
Implementation Method 4
subjecting a particle selected from an aerogel, carbon black, a metal oxide and silica having a hydrophobic surface with an alkaline solution
Implementation Method 5
treating said particle having said hydrophilic region with at least one silane treating agent
Data Source
AI summary
A particle containing a hydrophobic region and a hydrophilic region, products containing the same, a process of making the same, and uses thereof are described. A process of making the particle is also described wherein UV/Ozone techniques can be used to control the depth of organics removal from a porous hydrophobic particle such as an aerogel. The particles can be used in a variety of applications, such as a monolith, a building block, an optical waveguide, a blanket, a matting agent, a structural composite panel, a glass-fiber reinforced panel, a window, a separation wall, a composite wall, a temperature insulation panel, a sound insulation panel, a moisture resistant article, a syntactic foam, or any product of manufacture containing the particles.