No 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.

No abstract

For water injection development in low-permeability reservoirs, nanoscale SiO2-fluorinated acrylate polymer nanoemulsions (SCFs) with good properties were prepared through core–shell emulsion polymerization. The results show that nano-SiO2 particles are well dispersed, the average particle size of the SCFs is 113 nm, and the synergy among fluoride chain segments is good and effectively improves the utilization of fluorine atoms. SCFs form a low-surface-energy nanoscale hydrophobic film on the rock surface, which changes the original rock surface micro- or nanostructure, resulting in a water contact angle of up to 120° at the core. At 60 °C, the interfacial tension (IFT) between a 1500 mg/L SCF dispersion and white mineral oil is 1.86 mN/m, decreasing by 95.67% relative to the oil–water IFT at room temperature. The core flooding experiment shows that the depressurization rate reaches 29.62% in the 1500 mg/L SCF dispersion. Therefore, SCFs have broad application prospects in processes that eliminate water lock, reduce injection pressure, and increase injection volume.