Preparation Of Long Durability Fluid-solid Surface And Its Corrosion Resistance

Corrosion is the major enemy for metal materials used in seawater.The corrosion protection of hydrophobic surface has attracted an increasing attention in recent years.The gas-solid superhydrophobic surface can protect the underlying metal from corrosion because of isolating the metal and corrosive medium of the air cushion formed in the rough structure.However,the applications of these materials in underwater environment have been blocked due to the intrinsically short sustainability of the gas dissolving.Two methods have been investigated to solve short sustainability of the superhydrophobic surface.Oil is used to form a stable system with the rough surface since it is insoluble with water and will not escape under water pressure.The other way to realize long durable superhydrophobicity is continuously injecting air to compensate the air cushion.Both of the two structures can realize long durable superhydrophobicity surface and exhibit an excellent anti-corrosion ability in marine environment.In this paper,SLIPS is constructed via a dissolution-deposition strategy.Firstly iron tetradecanoate was formed by an electrochemical route onto steel surface,and then fluid lubricant was infused into the deposit to form a stable oil-solid system.The surface morphology,composition distribution,wettability and roughness were analyzed by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),a contact angle meter(CAM-101,KSV Instruments),and 3D laser confocal microscope(Olympus LEXT OLS4000).The affection of dissolution time and solution conductivity were explored.Otherwise,the corrosion resistance of SLIPS is investigated.Results show that the water contact angle with hydrophobic surface reached 152.45°.Morphology consisting of discontinuous pumps was related with electrolytic time and solution conductivity.The Icorr of the PFL/TAH/LS-20?L was about 1/10 lower than that oflow alloy steel and TAH,but corrosion occurred as the immersion time prolong.Once add the oil volume to 40?L,60?L and 80?L,the Icorr dropped 6 orders of magnitude.Meanwhile as immersion time prolong,no corrosion happened.It showed that the SLIPS has a better anti-corrosion ability.The other way to realize long superhydrophobicity is to increase the air content.In this study,long superhydrophobicity sponge was obtained by chemical treatment and uninterrupted air injection.The contact angle with water of the as-prepared sponge reached163.6°.Meanwhile,humidity densitive resistor was used to monitor the humidity changes in the sponge.Results show that after immersed in NaCl solution for 46 h,the Icorr of needle parceled in sponge shifted 10 times.As immersion time prolong,the air escaped and superhydrophobicity sponge failed.But with continuous aeration,the Icorr of needle changed little.It showed that with continuous aeration,the sponge will not fail for a long time and can realize long durability superhydrophobicity.