Figure 2. (A) The coated glass exhibited an optical transmission close to that of its uncoated counterpart. (B) Photograph of a smartphone screen covered by the coated glass in the middle region that is outlined by white dashed lines. (C) AFM image of the coating surface. (D) Photograph of the minimum bending radius measurement of the coated PET. (E) The coating maintained its anti-adhesion performance against oil-based ink after it had been subjected to 1000 abrasion cycles. (F) Antiadhesion performance against oil-based ink after the coatings had been immersed into NaOH (pH = 14), HCl (pH = 0), and NaCl solutions (10 wt%) for 7 h, 16 h, and 15 d, respectively. (G) The sliding behaviour of cooking oil before and after the coating had been immersed in this oil for 15 d. (H) The CAs of various liquids exhibited negligible changes after the coatings had been immersed in these liquids for various lengths of time.
The coating also possesses excellent transparency, flexibility, and durability. The optical transmission of uncoated and coated glass slides exhibited negligible differences in the visible light range (400-750 nm, Fig. 2A). The glass slide bearing the transparent coating did not obscure the screen (Fig. 2B), indicating its potential applicability for electronic displays or devices. This optical clarity could be attributed to the flatness of the coating surface, thanks to the excellent miscibility of the silicon precursors and the lack of solvent volatilization disturbance in this solvent-free system. The atomic force microscopy (AFM, Fig. 2C) image indicated that the root-mean-square surface roughness was only ~ 0.5 nm, while the SEM (Fig. S4) image revealed that the coating possessed a featureless surface with no evidence of structures or roughness above the micrometer scale. A minimum bending radius of less than 1 mm was reached for the coated PET (Fig. 2D). This excellent flexibility and foldability would expand a diverse range of coating applications, including the coating of soft pipelines, as well as flexible materials or devices for prosthetics and advanced robotics. The coating possessed a hardness rating of HB according to the ASTM D3363 protocol, and the oil-based ink could still be completely removed from the coating even after it had been subjected to 1000 abrasion cycles with cotton fabric under a load of 500 g (Fig. 2E). The coatings maintained their long-term anti-adhesion performances even after they had been immersed in basic, acidic, salt solutions, and oil (Fig. 2F and G). The negligible chemical change of the coating surface after the immersion in different liquids for various lengths of time has been confirmed via CA measurements (Fig. 2H) and XPS (Fig. S7). With the high crosslinking density that is induced by the low molecular weight of processors, the migration of interfacial segments as well as the chemical reconstruction at the interfaces of the coating and ambient liquids would be restrained.