**4. Conclusions**

*Novel Nanomaterials*

**coatings**

**324**

**Figure 5.**

*stearate to remove the GO dust.*

*Superhydrophobic applications of ZnO/magnesium stearate (a) dye repellency, (b) urine repellency, (c) spreading of graphene oxide (GO) dust on coatings, the (d) self-cleaning ability of ZnO/magnesium* 

copper stearate coatings possess a trapped air film on their exterior surfaces leading to an excessive displaced volume of water. The entire phenomenon can be termed as super-buoyancy [48]. These studies demonstrated the plastron effect's vital role in the ZnO/copper stearate coatings' floating properties. The ZnO/copper stearate coatings' load-bearing characteristics are investigated by loading known mass (stapler pins) on their top surface during floating, as shown in **Figure 4(B)**. It showed that after loading a few stapler pins, there are no signs of sinking for the ZnO/copper stearate coatings. The effect of thickness of superhydrophobic ZnO/copper stearate coatings via different deposition times (180 to 1800 seconds) on their load-bearing properties is provided in **Figure 4(C)**. It showed that ZnO/copper stearate coatings with a high thickness (weight of about 0.062 g) remain floating and can bear about 0.3667 g (19 stapler pins) without sinking issues. **Figure 4(C)** illustrated that the ratio of net floating weight to the weight of ZnO/copper stearate coating decreases with increasing thickness. This can be explained based on the more inert/dead layers present in the coatings with high thickness. On the other hand, the capability of load-bearing is superior for thin coatings (deposition at 30 seconds) that can bear 52 pins (~333 times higher than their net weight). The findings on the floating and load-bearing characteristics of the superhydrophobic ZnO/copper stearate coatings can be applied

**3.6 Applications of superhydrophobic coatings towards self-cleaning urinary** 

The superhydrophobic coatings' self-cleaning properties can be used for developing water-free urinaries, which doesn't require any systematic cleaning process to mollify unpleasant odor [49, 50]. Since the surface tension of water (71.2 mN/m) and urine (70 mN/m) are of similar values, it is expected that a water-repellent surface possesses a tendency to repel urine as well [51, 52]. The ZnO/magnesium stearate coatings showed excellent dye and urine-repellant properties, as shown in **Figure 5(a, b)**. It is observed that the droplets of urine samples roll off over the surface of ZnO/magnesium stearate coatings due to their extreme repellent

for water floating micro-robots and surveillance applications.

In conclusion, the significant role of porous nanostructures for developing superhydrophobic coatings is demonstrated in this chapter. A cost-effective sonochemical approach combined with a spray coating process for the fabrication of superhydrophobic coatings is presented. The impact of nanostructures on the coatings' porosity is explained with the experimental findings like AFM micrograph and water contact angle measurements. The exciting applications of superhydrophobic coatings like water-floating properties, load-bearing applications, dust removal, self-cleaning urinary coatings are illustrated in this chapter.
