Long-lasting superhydrophobic products
The UCA partner has pioneered a synthesis route to produce long-lasting superhydrophobic products with high penetration and suitable adherence to the building substrates for application in stone, roof tiles and other building materials. Specifically, superhydrophobicity is produced by adding silica nanoparticles and an alkylsiloxane, such as polydimethylsiloxane, to the UCA consolidant. The organic component reduces the surface free energy of the material, resulting in hydrophobicity behaviour and the SiO2 NPs produce a coating of closely packed particles. The effect of this is to trap air beneath the water droplets, thus significantly minimizing the contact area between droplet and surface, giving rise to a Cassie-Baxter state.
Therefore, this route is the starting point to produce a multifunctional impregnation treatment with two different objectives:
- to promote a consolidant effect by producing C-S-H gel;
- to produce a superhydrophobic concrete surface.
Left: Water droplet behaviour in a Wenzel state and a Cassie-Baxter state (superhydrophobic behaviour). Right: Behaviour of water droplets on roof tile samples treated with a superhydrophobic product, developed in the UCA laboratory.