Viscous Oil De-Wetting Surfaces Based on Robust Superhydrophilic Barium Sulfate Nanocoating

Abstract

Viscous oil adherence onto solid surfaces is ubiquitous and has caused intractable fouling problems, impairing the function of solid surfaces in various areas such as optics and separation membranes. Materials with superhydrophilicity and underwater superoleophobicity are very effective in elimination of oil fouling. However, most of them cannot dewet viscous oils and may malfunction without prehydration treatment. Herein, we report a facile and environmental strategy to prepare barium sulfate (BaSO 4 ) nanocoating to dewet viscous oils on dry surfaces. Abundant surface polar groups (surface hydroxyl) on BaSO 4 nanocoating enhance both hydrophilicity after oil fouling (underoil water contact angle <10°) and underwater superoleophobicity (underwater−oil contact angle >155°) and then facilitate oil dewetting ability. Different oils with viscosity up to 900 mPa•s can be easily eliminated after immersion into water. The results and force analysis also demonstrate that small surface roughness and ultrahydrophilicity under oil are beneficial to achieve oil dewetting property on dry surfaces. Furthermore, BaSO 4 nanocoating displays excellent mechanical, thermal and chemical stability and can maintain oil repellency through various harsh conditions. Outstanding antioil fouling ability also enables the fabric coated by BaSO 4 nanocoating to separate crude oil/water with flux higher than 28 000 Lm 2− h −1 and separation efficiency larger than 99.9% and maintain effective separation performance even after 100 times of separation. Thus, the robust superhydrophilic BaSO 4 nanocoating is potential in oil dewetting and waste oil remediation.

Bioinspired Superspreading Surface: From Essential Mechanism to Application

“…After rinsing the surface with water, the adhered oils on superspreading AAO could be completely removed, which facilitates the system being able to tolerate 130 on–off cycles without attenuation (Figure c,d). A facile and environmental superspreading barium sulfate (BaSO 4 ) coating was prepared by Deng et al, whose ST in air and under oil were 2.6 and 8.8 s, respectively, and where oil with a viscosity of 900 mPa s could be eliminated after immersing the coated surface into the water …”

“…A facile and environmental superspreading barium sulfate (BaSO 4 ) coating was prepared by Deng et al, whose ST in air and under oil were 2.6 and 8.8 s, respectively, and where oil with a viscosity of 900 mPa s could be eliminated after immersing the coated surface into the water. 50…”

Structure–Activity Relationship between the Superhydrophilic Nanowire Structure and the Oil Dewetting Property

“…However, some studies have reached the opposite conclusion. The surface microstructure will trap oil droplets and prevent them from desorption. , Also, the specific oil dewetting effect is affected by various structural factors. − Superhydrophilicity is the prerequisite of oil droplet desorption. Only when the surface has a strong enough affinity for water can water enter between the surface and the oil droplet to separate them.…”

Eco-friendly Dopamine-Modified Silica Nanoparticles for Oil-Repellent Coatings: Implications for Underwater Self-Cleaning and Antifogging Applications

“…Nevertheless, some researchers found specific anion groups in zwitter polyelectrolytes determining their hydration ability, which has a decisive influence on their wettability. , Surfaces modified by this type of polymers were reported to achieve oil repellency and degreasing. − After grafting specific zwitterionic polymers, solid surfaces possess underoil superhydrophilicity, which endows them with outstanding underwater self-cleaning performance. Oil can detach once the oil-wetted surfaces were immersed into water.…”