Flexible superomniphobic doubly re-entrant (Dual-T) microstructures inspired by springtails have attracted growing attention due to their excellent liquid-repellent properties. However, the simple and practical manufacturing processes of the flexible Dual-T microstructures are urgently needed. Here, we proposed a one-step molding process coupled with the lithography technique to fabricate the elastomeric polydimethylsiloxane (PDMS) Dual-T microstructure surfaces with high uniformity. The angle between the downward overhang and the horizontal direction could reach 90° (vertical overhang). The flexible superomniphobic Dual-T microstructure surfaces, without fluorination treatment and physical treatments, could repel liquids with a surface tension lower than 20 mN m–1 in the Cassie–Baxter state. Owing to the excellent robustness of the one-step molding downward overhanging, the max breakthrough pressure of this surface could reach up to 164.3 Pa for ethanol droplets. Furthermore, the flexible superomniphobic Dual-T surface allowed impinging ethanol droplets to completely rebound at the Weber number up to 7.1 with an impact velocity of ∼0.32 m s–1. The Dual-T microstructure surface maintained excellent superomniphobicity even after surface oxygen plasma treatment and exhibited excellent structural robustness and recoverability to various large mechanical deformations.

Doubly re-entrant surfaces inspired by springtails exhibit excellent repellency to low-surface-tension liquid. However, the flexible doubly re-entrant surfaces are difficult to fabricate, especially for the overhang of the structure. Herein, we demonstrate a simple Fresnel aperture diffraction modulation strategy in microscale lithography coupled with a molding process to obtain the flexible doubly re-entrant superomniphobic surfaces with nanoscale overhangs. The negative nanoscale overhang features were formed in a single-layer photoresist due to the fine-modulation of the optical intensity fluctuation of the Fresnel aperture diffraction. The as-prepared flexible non-fluorinated polydimethylsiloxane (PDMS) doubly re-entrant microstructure based on the Fresnel aperture diffraction (D-BF) surface (without any additional treatments) could repel ethanol droplets (21.8 mN m–1) in the Cassie–Baxter state. The robust nanoscale overhangs obtained by the molding process enable the maximum breakthrough pressure for the low-surface-tension ethanol droplets on the D-BF surfaces up to about 230 Pa, allowing ethanol liquids with Weber numbers up to 8.7 to fully bounce off. The fabricated non-fluorinated D-BF superomniphobic surface maintains outstanding liquid repellency after the surface wettability modification and deformation test.