Underwater superpolymphobicity of the femtosecond laser-structured stainless steel. (a–c) Hierarchical microstructures of the stainless steel surface after femtosecond laser ablation. (d) In-air droplet and (e) underwater droplet of liquid polymer on the original stainless steel. (f) In-air droplet and (g) underwater droplet of liquid polymer on the laser-structured stainless steel. (h) Releasing a water droplet onto the structured surface. (i) Moving an underwater liquid polymer droplet to contact and then leave the structured stainless steel surface in water. Reproduced from [90
] with the permission.