Hydrophobic Cellulose Aerogel for Humidity-Stable Transparency
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Solution Overview
Problem
Cellulose porous bodies containing cellulose nanofibers (CNF) lose transparency in high-humidity environments due to water adsorption, which affects their heat-insulating properties.
Innovation Solution
A transparent heat insulating member comprising a cellulose porous body with cellulose nanofibers and a water-repellent component, featuring a fiber diameter of 3 to 40 nm and a contact angle of 90 degrees or greater with respect to water, utilizing a compound with a fluorinated alkyl group, such as an alkoxysilane, to maintain transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a cellulose porous body containing cellulose nanofibers is used as a heat insulating member, then excellent heat insulating properties are achieved, but transparency is insufficient and not maintained in high-humidity environments due to water adsorption
Solution Approach 1:
The patent applies parameter changes by modifying the surface properties of the cellulose porous body through water-repellent treatment. Specifically, the contact angle with water is increased to 90 degrees or greater, and the water absorption rate is reduced to 5% or less, thereby preventing water adsorption that would otherwise cause transparency loss in high-humidity environments while maintaining the heat insulation properties of the porous structure
Solution Approach 2:
The patent uses composite materials by combining cellulose nanofibers with water-repellent components. The cellulose porous body is treated with water-repellent agents such as fluorinated compounds or silane-based compounds, creating a composite structure that maintains both the excellent heat insulation properties of the porous cellulose network and the transparency required for the application
2Area of stationary object
If the cellulose porous body has a hydrophilic internal surface, then the structure provides high specific surface area and porosity, but water adsorption occurs leading to loss of transparency
Solution Approach 1:
The patent applies local quality by treating only the internal surface of the cellulose porous body with water-repellent components. The bulk cellulose structure maintains its porous network and high specific surface area properties, while the internal surface is locally modified to be hydrophobic with a contact angle of 90 degrees or greater, preventing water adsorption at the critical interface where transparency is affected
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 solution maintains transparency in high-humidity conditions by reducing water adsorption on the cellulose porous body, ensuring effective heat insulation.
Implementation Method 1
the cellulose porous body contains a cellulose nanofiber and a water-repellent component, and the cellulose porous body has a fiber diameter of 3 to 40 nm... the contact angle of 90 degrees or greater with respect to water
Implementation Method 2
Since the cellulose porous body containing CNF is an aerogel, the cellulose porous body has excellent heat insulating properties
Data Source
AI summary
An object of the present invention is to provide a transparent heat insulating member which can maintain transparency in a high-humidity. The transparent heat insulating member according to the embodiment of the present invention is a transparent heat insulating member including a cellulose porous body, in which the cellulose porous body contains a cellulose nanofiber and a water-repellent component, and the cellulose porous body has a fiber diameter of 3 to 40 nm.