Anti-Oil-Adhesion Property of Superhydrophilic/Underwater Superoleophobic Phytic Acid-FeIII Complex Coatings

Crude oil adhesion issues are widespread in the petroleum industry, leading to inefficient production and high maintenance costs. Developing efficient antifouling materials and investigating the microscopic adhesion mechanism are of substantial significance. In the present work, a superhydrophilic/underwater superoleophobic PAFC coating with excellent antifouling properties was constructed by the coordination-driven self-assembly of phytic acid (PA) and FeCl₃ (FC). The atomic force microscope (AFM) droplet probe technique was employed to elucidate the underlying mechanism of the anti-oil-adhesion property of the PAFC coating. Results showed that the PAFC modification achieved the optimum effect at a molar ratio of 1:3 between PA and Fe^III. Applying a (3-aminopropyl)triethoxysilane (APTES) interlayer can effectively improve the performance of the PAFC coating on silica substrates. AFM droplet probe experiments indicated that the adhesion force between submerged micrometer-sized oil droplets and PAFC-modified substrates was significantly weaker than that with the untreated substrate. Meanwhile, the adhesion forces between oil droplets and surfaces were inversely proportional to the contact angle of the oil in water and were enhanced by higher salinity, lower collision velocity, and stronger loading force. The oil injection and wall sticking tests also confirmed the effectiveness of the PAFC modification in resisting the adhesion of crude oil.