SEM observations reveal that original CGF exhibits a relatively smooth surface with tiny wrinkles, while PFOTES-CGF show a coarse surface covered with a large number of nanoparticles (Fig. 1). From a lower magnification (500 , 2000 ), CFG itself is also a cylindrical, straight with a thin wall relative to its diameter and a hollow tube-like structure without convolutions (Fig. S1, Supporting information). One can speculate that such a large lumen and hierarchical structured roughness are helpful for improving effectively its oil-absorbing property.