Superhydrophobic coatings on meta-aramid papers enabled by mechanical interlocking for anti-thermal aging applications

Abstract The durability of superhydrophobic coatings has emerged as a pivotal consideration for their practical applications. Conventional methods for preparing robust superhydrophobic coatings often incorporate chemical binders. However, these binders are susceptible to melting and embrittlement under high temperatures, greatly limiting their stable service life, particularly in complex outdoor environments. Herein, the meta-aramid papers are treated with superhydrophobic modification using the surface-embedded spray coating technique. Benefiting from the unique deprotonation and reprotonation features of meta-aramid fibers, the paper surface morphology is reconstructed into a porous micro-nano structure. Given the comparable dimensions between the hydrophobic nano-SiO2 particles and the surface pores, the SiO2 particles become surface-embedded within the pores, resulting in a firmly bonded superhydrophobic coating. Furthermore, additional hydrogen bonds are formed between the SiO2 particles and meta-aramid fibers, further strengthening their adhesion. The as-prepared paper can endure temperatures up to 260℃, preserving a contact angle >150° and a sliding angle <5°. It also exhibits exceptional abrasion durability even after thermal aging. Additionally, the DC wet flashover voltage maintains over 95% of its original value. Our surface-embedded strategy offers an innovative alternative to chemical binders and enhances the viability of superhydrophobic coatings for applications in high-temperature environments.