Fig. 1. Schematic of the sample processing flow and exploration results of femtosecond laser power and power density. (a) Flowchart of femtosecond laser processing of PEEK material; (b) schematic of femtosecond laser processing system; (c) when the defocus amount X is 0 and 3 mm, the relationship between surface contact angle and laser power; (d) effect of defocus amount X on the surface contact angle; (e) when the defocus amount X is -3.5, 0, and 3 mm, the relationship between surface contact angle and laser scanning speed

Fig. 2. Influence of laser scanning times and scanning speed on the surface contact angle. (a)(b) SEM images of the surface fabricated by femtosecond laser with different scanning speeds; (c)(d) SEM images of the corresponding enlarged regions; (e) surface contact angle versus scanning speed and scanning times

Fig. 3. Hydrophobicity test results of samples before and after fast scanning under four experimental parameters. (a) Contact angles and (b) sliding angles of samples treated by surface fast scanning with distilled water, milk, and juice; (c) contact angles and (d) sliding angles of samples without surface fast scanning with distilled water, milk, and juice

Fig. 4. EDS images of elements in PEEK surfaces. (a) Without laser processing; (b) after laser processing but without surface fast scanning; (c) after laser processing and surface fast scanning

Fig. 5. Hydrophobicity tests of PEEK material treated by femtosecond laser. (a) Schematic of femtosecond laser processing of PEEK material; (b) photograph of treated area of PEEK material using femtosecond laser; (c) photograph of treated area of PEEK material after being dipped in milk once; (d) photograph of untreated PEEK material after being dipped in milk once; (e) photograph of treated area of PEEK material after being dipped in milk 50 times