Silicone oil infused slippery candle soot surface for corrosion inhibition with anti-fouling and self-healing properties

Abstract

Creating superhydrophobic materials that effectively protect metal from corrosion would bring great benefits for human safety and national economy. However, most of these materials suffer from poor anti-corrosion and liquid repellence which severely restrict their actual applications. Recently, the slippery liquid-infused porous surface (SLIPS) was proposed to address the problems of metal corrosion. But the trouble is how to avoid complicated manufacturing processes as well as high production costs. Herein, a low-cost micro/nano-structured candle soot coating (CSC) was successfully fabricated via a facile spraying approach, which realized superhydrophobicity with the water contact angle larger than 150° and sliding angle smaller than 10°. Unfortunately, the superhydrophobic CSC possessed limited repellence against organic liquids and poor corrosion resistance. Through the infusion of silicone oil on the superhydrophobic surface, the SLIPS showing outstanding anti-corrosion capability can be achieved. The corrosion current density of SLIPS after immersion in 3.5 wt% NaCl solution for 2 h is 10 and 100 times smaller than that of the superhydrophobic CSC and magnesium sheet, respectively. Moreover, the long-time corrosion behavior of SLIPS was investigated by the electrochemical impedance spectroscopy, which further indicated that SLIPS presented a superior application value in anti-corrosive protection. Furthermore, the water contact angle of SLIPS changed slightly after physical cutting compared with the original contact angle, suggesting that SLIPS behaved smart self-healing property. From the comparison of the anti-corrosive and liquid-repellent properties towards the superhydrophobic CSC and SLIPS, there is no doubt that the as-prepared SLIPS would play a significant role in many fields.