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Transparent coatings made from spray deposited colloidal suspensions
B Fleury1, G Dantelle, S Darbe
1Groupe de Chimie du Solide, Laboratoire de Physique de la Matière Condensée, UMR CNRS 7643, École Polytechnique, 91128 Palaiseau, France.
Langmuir : the ACS Journal of Surfaces and Colloids
|April 26, 2012
Summary
Creating optically active coatings using spray-deposited nanoparticles is possible. Surprisingly, less stable nanoparticle solutions yield smoother, more transparent coatings by controlling the coffee-ring effect and surface roughness.
Area of Science:
- Materials Science
- Nanotechnology
- Optics
Background:
- Optically active coatings are crucial for various applications.
- Controlling nanoparticle aggregation and film morphology is key to tuning optical properties.
- The coffee-ring effect significantly impacts coating uniformity and optical transmission.
Purpose of the Study:
- To develop few-micrometer thick optically active coatings using spray-deposited nanoparticles.
- To investigate the influence of nanoparticle aggregation state on coating properties.
- To control optical scattering by suppressing the coffee-ring effect.
Main Methods:
- Spray deposition of nanoparticle coatings.
- Modification of colloidal solution stability to alter nanoparticle aggregation.
- Analysis of surface roughness and optical transmission of the resulting films.
- Demonstration using titanium dioxide (TiO2) and yttrium vanadate (YVO4:Eu) nanoparticles.
Main Results:
- Altering nanoparticle aggregation state changes film surface roughness and optical transmission.
- Less stable colloidal solutions resulted in smoother coatings compared to highly stabilized ones.
- Smoother coatings exhibited higher optical transparency.
- The phenomenon was observed for both TiO2 and YVO4:Eu nanoparticles.
Conclusions:
- A non-stable colloidal solution can lead to smoother, more transparent coatings than a stable one.
- Controlling the coffee-ring effect through nanoparticle aggregation is an effective strategy for optical coating design.
- This approach is generalizable to various nanoparticle systems for optical applications.
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