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Hollow polymer-silica particles offer sustainable alternative to TiO₂ in coatings
Researchers have achieved a breakthrough in coating technology by replacing TiO₂ with hollow polymer-silica particles, delivering superior optical performance and reduced environmental impact.
Titanium dioxide (TiO₂) has long been a staple ingredient in coatings due to its exceptional opacifying properties. However, its production is associated with significant environmental challenges, prompting the search for sustainable alternatives. In a new study, researchers have successfully replaced TiO₂ with hollow polymer-silica particles (HPs), achieving comparable or superior optical performance.
Using 3-(trimethoxysilyl)propyl methacrylate (TPM) hollow particles, the team investigated various particle sizes and shell thicknesses under different environmental conditions. Smaller HPs (1 μm diameter, 0.2 μm shell thickness) demonstrated remarkable optical properties, achieving solar reflectance values of up to 73.3 % across the visible and near-infrared spectrum. These coatings outperformed both larger HPs (∼5 μm diameter, 0.25 μm shell thickness) and TiO₂ reference coatings with the same mass percentage of opacifier.
Reading tip: Titanium Dioxide
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Enhanced performance and industrial reliability
The study also revealed that the distribution of hollow particles within the coating, influenced by factors like diffusion, evaporation, and sedimentation, had minimal impact on optical performance. This reduced sensitivity to particle distribution enhances the reliability of hollow polymer-silica particles in industrial formulations.
The robust performance of these coatings in three different environments further underscores their commercial viability. By eliminating the need for TiO₂, this innovation offers both environmental and economic benefits, paving the way for more sustainable coating technologies.
Source: Sofroniou, C. et al., Hollow polymer-silica particles as an alternative to TiO₂ opacifiers. Progress in Organic Coatings, 2025. DOI: https://doi.org/10.1016/j.porgcoat.2025.109817.
