Nanocasting Technique to Prepare Lotus-leaf-like Superhydrophobic Electroactive Polyimide as Advanced Anticorrosive Coatings

Abstract

Nanocasting technique was used to obtain a biomimetic superhydrophobic electroactive polyimide (SEPI) surface structure from a natural Xanthosoma sagittifolium leaf. An electroactive polyimide (EPI) was first synthesized through thermal imidization. An impression of the superhydrophobic Xanthosoma sagittifolium leaf was then nanocasted onto the surface of the EPI so that the resulting EPI was superhydrophobic and would prevent corrosion. Polydimethylsiloxane (PDMS) was then used as a negative template to transfer the impression of the superhydrophobic surface of the biomimetic EPI onto a cold-rolled steel (CRS) electrode. The superhydrophobic electroactive material could be used as advanced coatings that protect metals against corrosion. The morphology of the surface of the as-synthesized SEPI coating was investigated using scanning electron microscopy (SEM). The surface showed numerous micromastoids, each decorated with many nanowrinkles. The water contact angle (CA) for the SEPI coating was 155°, which was significantly larger than that for the EPI coating (i.e., CA = 87°). The significant increase in the contact angle indicated that the biomimetic morphology effectively repelled water. Potentiodynamic and electrochemical impedance spectroscopic measurements indicated that the SEPI coating offered better protection against corrosion than the EPI coating did.

Superhydrophobic surfaces for corrosion protection: a review of recent progresses and future directions

“…9). [94][95][96][97] Compared to flat coating, the microstructured coating exhibits improved barrier performance against water thanks to the inclusion of air within the microstructures, thereby improving the protection capability of layer for metal substrate. In addition, nanoparticles, such as clays 98 or graphene, 99 have been incorporated to these coatings to decrease oxygen permeability.…”

Preparation of superhydrophobic polyimide films modified with organosilicasol as effective anticorrosion coatings

“…With their precise size control, tunable surface chemistry, and high processability through spin-or dip-coating, NPs appear to be excellent materials for producing superhydrophobic coatings [22][23][24][25][26][27][28][29][30]. These techniques for preparing superhydrophobic PI coating could be promising in application for anti-corrosion and anticontamination use in harsh environment [31][32][33].…”

Biomimetic electroactive polyimide with rose petal-like surface structure for anticorrosive coating application

“…The characteristic peak found at 1365 cm -1 was assigned to C=N stretching. In Figure 3b, the FTIR spectrum of EPI revealed a characteristic absorption band at 742 cm -1 , which corresponds to the deformation of the imide group [39].…”