International. Scientists from Brazil and Portugal developed an efficient and durable self-cleaning acrylic paint containing mesoporous Microspheres of TiO2.
Self-cleaning paints are able to remove undesirable substances on their surface in the presence of the incidence of light. However, photoclimitation is not selective and, in addition to contaminants, the polymer's paint matrix can degrade. Therefore, in order to develop a proper self-cleaning paint formulation, it is necessary to find a balance between non-selective activity and film degradation.
In a current study, TiO2 (MTiO2) microspheres were synthesized, characterized and incorporated into a water-based acrylic paint formulation with the aim of modulating the photocatalytic effect of TiO2 particles and increasing the durability of the paint. In addition to the synthesized photocatalyst, commercial TiO2 particles (P25, manufactured by Evonik) were also evaluated and used as a reference. Comparatively, a commercial paint containing rutile TiO2 as a pigment was evaluated.
The photoclimatization efficacy of paint films was determined by a new analysis method based on multiple cycles of adsorption and exposure to UVC light in a solution of methylene blue. After the cyclic test, the stability of the paint films was evaluated using scanning electron microscopy (SEM). In aqueous suspension and under UVC light, the MTiO2 showed photoactivity similar to that of the P25. The incorporation of photocatalysts into paint films initially reduced activity by around a factor of 5, due to limitations related to the access of pollutants and light to TiO2 particles.
Paint with built-in MTiO2 was found to be more stable than reference paint with added P25, after cyclic analysis. Finally, paint containing MTiO2 showed degradation similar to that of commercial rutile paint under the same extreme conditions of cyclic analysis.
Source: www.sciencedirect.com
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