Multifunctional wall coating combining photocatalysis, self-cleaning and latent heat storage

Abstract

Mortars, one of the most common construction materials, have not received any substantial modification for many decades. This has changed in recent years; new compositions are now being developed, with new properties, using nano-additives, fibres and capsules. In this work, surfaces with new and innovative functionalities that promote energy savings and improve air quality have been developed and studied. Incorporation of phase change materials (PCM) and titanium dioxide (TiO 2) nanoparticles in construction products is currently under study by different research groups. However, these studies only address their incorporation separately. Adding new additives into the mortar's matrix can be complex-due to microstructural modifications that will influence both fresh and hardened state properties. Moving from a single additive to multiple additions, as in this study, increases the system's complexity. Only with a good understanding of the microstructural properties, it is possible to add multiple additives (including nano and microparticles) to mortars, without damaging its final quality. This work demonstrates that a higher additive content is not always a guarantee of better results; lower additions can often provide a better compromise between performance and final mechanical properties. The results presented in this paper confirmed this and show that combining PCM microcapsules and TiO 2 nanoparticles open a new path in the development of mortars with multiple functionalities. In this study, a new material with depolluting, self-cleaning and heat storage was created. For the development of new and innovative mortars, a proper balance of multiple additives, supported by the study of microstructural changes, can lead to an optimization of the compositions, ensuring that the mortar's final properties are not affected.

The Preparation of TiO2 Film by the Sol-Gel Method and Evaluation of Its Self-Cleaning Property

“…Kim et al [ 23 ] synthesized a layer of water-resistant and surface-coatable C-PEG (poly(ethyleneglycol)-g-[poly(dimethylaminomethacrylate)]) with TiO 2 nanoarticles (NPs) on a glass surface via catechol chemistry and they found that the final product gained self-cleaning capabilities owing to the hydrophilic nature imparted to the surface by controlling the amounts of catechol moiety and TiO 2 NPs on the polymer. Lucas et al [ 25 ] combined phase change materials (PCM) microcapsules and TiO 2 nanoparticles together and found it made mortars with multiple functionalities including self-cleaning properties. Zhang et al [ 26 ] produced a nano-TiO 2 polyacrylate hybrid dispersion and successfully fixed it on cotton fabric.…”

Properties of Cement with Photocatalytic Composite Material

“…4) show that the use of diatomite allows increasing the strength of the cement stone, which is reasoned by the compaction of the structure by the products of the pozzolanic reaction. Their formation during the use of PCM makes it possible to neutralize the negative effect of anatase [17] on the strength of the cement stone.…”

Evaluation of latent heat storage in mortars containing microencapsulated paraffin waxes – a selection of optimal composition and binders

“…This is the case with a recent work where paraffin microcapsules and titanium dioxide nanoparticles have been added to a lime mortar. The presence of the PCM improved the mechanical strength of the mortars containing nanoparticles [14].…”