Abstract
Phase-separation of nanorods and nanospheres has been explored at various locations within the deposits on gradient patterned surfaces using droplet evaporation technique. It has been observed that the motion of contact-line of suspension droplet on such surfaces prompts distinct shape separation effect. On the basis location on such surfaces, we can easily divide the deposition region into following sections. Initially on second set of stripes (where the contact-line initially pins), nanoparticle deposits are dense and widespread covering nearly the whole width of hydrophilic stripes. However, at the periphery of such deposits, phase separation of spheres and rods has been witnessed. Subsequently after the first dense deposition of nanoparticles, considerably less dense and centered islands of nanoparticle are observed. Nonetheless, within such islands, distinct phase separation of sphere-rich and rod-rich regions are observed at the middle of the hydrophilic stripes. Similarly, at the interfacial region between the two set of stripes, deposits are again very dense and widespread, however, phase separation of rods and spheres within such deposits is also observed at various locations. Lastly on third set of stripes, centered and relatively low dense islands of nanoparticles are observed. Once more, we observed distinct phase separation effect of rods and spheres within all connected and isolated islands.