A self-assembly and high-robustness super-hydrophobic coating based on waste marble powder

Uncontrolled waste marble powder contributes negatively to the environment. This paper reports a cheap and facile method to prepare a super-hydrophobic self-cleaning coating with high-robustness by using waste marble powder as the basic components. The PFOTES (1H,1H,2H,2H-Perfiuorooctyltriethoxysilane) was selected as the modification agents which is self-assembled on the marble powder surface. A very low mass concentration of PFOTES (0.1208% wt.) increases the water contact angle of a coated sample from 11.3° to 138°. With the gradual increase of PFOTES, the water contact angle increases from 138° to 153°. The sliding angle value, however, varies from over 180° (the water droplet will not fall even it is turned upside down) to 6.8°, which represented the wetting model changing from Wenzel model to the Cassie-Baxter model. Thus, the super-hydrophobic self-cleaning coating is obtained. Besides, the coating showed an excellent robustness, no obvious contact angle and sliding angle differences were detected after 10 times' robustness test (the contact angle and sliding angle ranged from 147° to 155° and 6.8° to 8.5° respectively).