Superhydrophobic and self-cleaning behavior of Portland cement with lotus-leaf-like microstructure

Nanocasting technique was used to transfer lotus-leaf-like microstructure onto the cement surface. Lotus leaf and Poly (dimethylsiloxane) (PDMS) were used as the origin template and negative template for surface microstructure casting, respectively. The micro papillae were successful replicated on the cement surface with high fidelity to lotus leaf microstructure. Viscosity of cement paste plays an important role in the nanocasting process. Lotus-leaf-like microstructure on cement surface was fabricated when viscosity deceased to 0.09 Pa.S. The equilibrium contact angle is about 140 on superhydrophobic cement surfaces as for the optimal specimen. The Cassie-Baxter model can be used to explain the variation of water contact angle with rough ratio as well as viscosity of cement paste. Measurement of rolling-off contact angle confirmed the superhydrophobic behavior of cement. The self-cleaning properties of the superhydrophobic cement were proved by T marker experiment with a potential application in future. (C) 2017 Elsevier Ltd. All rights reserved.