Thermochromic Fenestration Films with Vanadium Dioxide Nanocrystals
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Solution Overview
Problem
Current thermochromic materials face challenges in integrating high visible light transmission, low light scattering, and long-term physical integrity for dynamically tunable fenestration elements, particularly in thermally cycled applications.
Innovation Solution
A composition comprising a polymeric matrix with crystalline vanadium oxide nanomaterials, where the nanomaterials have dimensions between 5 nm and 100 nm, providing thermochromic modulation of NIR solar flux without impacting visible light transmittance, and are encapsulated in a shell to enhance stability and dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If thermochromic materials are integrated into fenestration elements to achieve NIR light transmittance modulation, then solar heat gain is reduced, but visible light transmission and optical clarity deteriorate
Solution Approach 1:
The patent applies local quality by making the vanadium oxide nanomaterials' optical properties temperature-dependent. At different temperatures, the material exhibits different optical characteristics: in the insulating phase it allows high visible light transmission, while in the metallic phase it blocks NIR light. This local differentiation of optical properties at the nanomaterial level resolves the contradiction between visible light transmission and solar heat gain reduction.
Solution Approach 2:
The patent utilizes parameter changes by exploiting the thermochromic transition of vanadium oxide nanomaterials. The material's optical parameters (transmittance, reflectance) change dramatically with temperature. By controlling the temperature parameter, the system dynamically adjusts between high visible light transmission and high NIR blocking, resolving the contradiction between these two opposing requirements.
2Loss of energy
If thermochromic nanomaterials are dispersed in polymeric matrices to achieve dynamic optical modulation, then NIR transmittance is modulated, but physical integrity during thermal cycling deteriorates
Solution Approach 1:
The patent applies the nested doll principle by embedding vanadium oxide nanomaterials within a polymeric matrix. The nanomaterials are nested at the nanoscale within the polymer structure, creating a composite where the polymer provides structural integrity and the nanomaterials provide thermochromic functionality. This nested structure maintains physical integrity during thermal cycling while enabling NIR transmittance modulation.
Solution Approach 2:
The patent uses composite materials by combining vanadium oxide nanomaterials with polymeric matrices. This composite structure leverages the strengths of both components: the nanomaterials provide thermochromic optical modulation while the polymer matrix provides mechanical stability and durability during thermal cycling. The composite nature resolves the contradiction between achieving NIR modulation and maintaining physical integrity.
3Loss of energy
If conventional thermochromic materials are used to block NIR light, then solar heat gain is reduced, but light scattering increases
Solution Approach 1:
The patent applies dimensionality change by transitioning from bulk thermochromic materials to nanoscale vanadium oxide nanomaterials. This dimensional reduction to the nanoscale allows the materials to block NIR light while minimizing visible light scattering. The nanoscale dimensions are small enough to avoid significant scattering of visible light wavelengths, resolving the contradiction between NIR blocking and light scattering.
Solution Approach 2:
The patent applies local quality by creating nanoscale regions with specific optical properties. The vanadium oxide nanomaterials have localized thermochromic properties that enable NIR blocking without affecting visible light transmission. This local differentiation at the nanoscale resolves the contradiction between achieving solar heat gain reduction and avoiding light scattering.
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 achieves significant NIR light transmittance modulation while maintaining high visible light transmission and optical clarity, effectively reducing solar heat gain without deleterious effects on the visible appearance, and is suitable for deployment in existing fenestration elements.
Implementation Method 1
thermochromic modulation of NIR solar flux represents an attractive route for controlling solar heat gain based on the ambient temperature
Implementation Method 2
thermochromic transitions are particularly important as a facile means of developing dynamically switchable glazing... Compounds that exhibit pronounced modulations of optical transmittance as a result of electronic transitions wherein the intrinsic electronic conductivity (carrier concentration and/or mobility) is dramatically altered
Implementation Method 3
a crystalline vanadium oxide nanomaterial dispersed in the polymeric matrix
Data Source
AI summary
Vanadium oxide nanomaterial composite compositions and substrates including films comprising vanadium oxide nanomaterial composite compositions are described. A film and composition generally including a polymeric matrix; and a crystalline vanadium oxide nanomaterial dispersed in the polymeric matrix, wherein the crystalline vanadium oxide nanomaterial comprises a smallest dimension between about 100 nm and about 5 nm.