Fig. 2.

Scanning electron microscopy images of micro- and nanocilia. (A) Microcilia with $r=1.5\hspace{0.17em}\mathrm{\mu }\text{m}$, $L=47\hspace{0.17em}\mathrm{\mu }\text{m}$, and density $=1\times 10^4\hspace{0.17em}{\text{cm}}^{-2}$. Images are made at different magnifications. (B) Microcilia with $r=1\hspace{0.17em}\mathrm{\mu }\text{m}$, $L=23\hspace{0.17em}\mathrm{\mu }\text{m}$, and density $=1\times 10^5\hspace{0.17em}{\text{cm}}^{-2}$. (C) Nanocilia with $r=350\hspace{0.17em}\text{nm}$, $L=9\hspace{0.17em}\mathrm{\mu }\text{m}$, and density $=7\times 10^5\hspace{0.17em}{\text{cm}}^{-2}$. (D) Nanocilia with $r=200\text{nm}$, $L=6\hspace{0.17em}\mathrm{\mu }\text{m}$, and density $=1\times 10^6\hspace{0.17em}{\text{cm}}^{-2}$. All the cilia are fabricated and aligned in one direction by applying an external magnetic field while drying them in the ambient conditions.