Antimony Doped Tin Oxide Nanoparticle Dispersion Without Dispersants
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Solution Overview
Problem
Existing nanoparticle dispersions in organic solvents often suffer from undesirable properties due to the presence of dispersants, such as adhesion and optical quality issues, and require cumbersome techniques to achieve multiple functionalities like electrical conductivity and heat absorption simultaneously.
Innovation Solution
Development of antimony or indium doped tin oxide nanoparticles in an organic solvent with latent reactive groups, prepared without dispersants, which react with the coating composition to provide coatings with excellent optical clarity, electrical conductivity, and heat absorption properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dispersants are used to prepare nanoparticle dispersions, then the nanoparticles can be dispersed in organic solvents, but the dispersants bloom to the surface and affect adhesion and optical quality
Solution Approach 1:
The patent removes dispersants from the nanoparticle dispersion system entirely. Instead of using conventional dispersants that bloom to the surface, the invention uses surface-modified nanoparticles with grafted organic groups that provide stability without compromising adhesion or optical quality. This extraction of the harmful element (dispersant) directly resolves the contradiction.
Solution Approach 2:
The nanoparticles are surface-modified with organic groups that enable them to self-disperse in organic solvents without requiring external dispersant agents. The surface modification allows the nanoparticles to maintain stability through their own surface properties, eliminating the need for dispersants that would otherwise be required.
2Manufacturing precision
If milling steps are used to create nanodispersion, then nanoparticles can be produced, but the process is time-consuming and produces micron-sized particles that cause defects
Solution Approach 1:
The nanoparticles are pre-synthesized with controlled size and surface modification before incorporation into the coating formulation. By performing the nanoparticle production and surface modification in advance with precise control, the patent eliminates the need for time-consuming milling steps during coating preparation, while ensuring uniform particle size that prevents defects.
3Adaptability or versatility
If multiple functionalities are added to coatings, then electrical conductivity and heat absorption can be achieved, but the coating composition becomes complex and optical clarity is compromised
Solution Approach 1:
The patent combines multiple functionalities (optical clarity, electrical conductivity, heat absorption) into a single integrated coating system using surface-modified nanoparticles. The organic surface groups on the nanoparticles enable them to interact with multiple coating components simultaneously, achieving multiple functions without requiring separate additive packages that would increase complexity.
Solution Approach 2:
The surface-modified nanoparticles serve multiple functions simultaneously: they provide optical clarity through their size and composition, enable electrical conductivity through their doping, and contribute to heat absorption through their thermal properties. This multi-functionality at the nanoparticle level eliminates the need for multiple separate functional additives, reducing overall composition complexity.
4Stability of the object's composition
If dispersants are used in nanoparticle dispersions, then nanoparticles can be kept in suspension, but the dispersants adversely affect the coating formulation properties
Solution Approach 1:
The patent eliminates dispersants from the system by using surface-modified nanoparticles that maintain suspension stability through their own surface properties. The organic groups grafted onto the nanoparticle surfaces provide steric stabilization and prevent aggregation without requiring external dispersant molecules, thereby removing the source of harmful effects.
Solution Approach 2:
The organic surface groups on the nanoparticles act as intermediaries that mediate their interaction with the organic solvent and coating formulation. These surface groups provide the necessary stability and compatibility without acting as separate dispersant additives, thereby eliminating the harmful effects associated with conventional dispersants while maintaining suspension 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 solution achieves high-quality coatings with enhanced scratch resistance, reduced reflection, and functionality such as antistatic properties or IR absorption, combining optical clarity with electrical conductivity and heat absorption without the drawbacks of dispersants.
Implementation Method 1
coatings providing heat absorption together with excellent optical clarity
Implementation Method 2
coatings providing electrical conductivity together with excellent optical clarity
Data Source
AI summary
The invention relates to a dispersion of antimony or indium doped tinoxide nanoparticles in an organic solvent, comprising a) 5-75 wt % of nanoparticles having a mean average size between 1 and 100 nm. b) a solvent comprising a hydroxyl group and an ether group. c) a water content of less then 15 wt %. d) a dispersant content of less then 0.1 wt %. The invention also relates to a method of making such a dispersion, by I. Making a mixture of an aqueous dispersion of antimony or indium doped tinoxide particles having an average size between 1 and 100 nm, a solvent comprising a hydroxyl group and an ether group, which forms an azeotrope with water, and a grafting compound. II. Heating the mixture under stirring at a temperature between 20 and 150° C. III. At least partially removing the solvent/water mixture. IV. Optionally adding more solvent. V. Repeating steps III and IV till the water content of the obtained dispersion is less then a desired value and the concentration solid is between 5 and 70 wt %.