Fabrication of Bioinspired Micro/Nano Textured Rough Surfaces Through the Scalable Roll Coating Process

Bioinspired Micro/Nano textured rough topography of a surface has many applications in super-hydrophobicity, self-cleaning surface, anti-icing coatings, anti-biofouling, and drag reduction surfaces. The role of hierarchical and complex surface topography in nature is to amplify the hydrophobicity and maximize the fouling resistance. Thus, a similar micro- and nano-scale 3-D topographic surfaces inspired from the nature were fabricated using a simple and scalable two roll coating process. This process was based on the ribbing instabilities associated with the shearing of non-Newtonian fluids between two rollers. The polymer composite retains the deformed shape due to the recovery of high-viscosity after removing the shear stress. The relationship between the process conditions and the textured structure were studied with the shear rate, capillary number and the surface roughness parameters (e.g., Wenzel factor and density of peaks). The results showed that the samples’ Wenzel roughness factor increased with the increase in shear rate up to a particular value and then decreased. Similarly, the density of peaks in the sample increased with an increase in capillary number up to a particular value and then decreased. These bioinspired surfaces with hierarchical textured patterns produced using two roll coating process show a tremendous potentiality to be used in super-hydrophobic, anti-biofouling, and drag reduction applications.