Inhibition of adhesion of CaCO₃ scale by polydopamine/polytetrafluoroethylene coating with stability and anticorrosion properties

Abstract

Reduction of calcium carbonate (CaCO 3 ) scale formation on the equipment surface is essential in a wide variety of industrial fields. In this work, polydopamine/polytetrafluoroethylene (PDA/PTFE) coating prepared by the simple immersion on stainless steel (SS) surfaces was developed to suppress the CaCO 3 scale adhesion. The PDA/PTFE-coated surface showed the higher hydrophobicity (water contact angle = 133.50 ) and lower surface free energy (11.92 mN/m) than the stainless-steel surface. The scale inhibiting rate of the coated surface was up to 76.8% after 12-hour immersion in the CaCO 3 solution in comparison with the untreated SS. More bubbles were observed on the PDA/PTFE-coated surfaces, and the number of bubbles increased with increasing solution temperature leading to less area for the scale adhesion. As a result, the PDA/PTFE coated surfaces have the higher antiscale ability at the higher solution temperature. Furthermore, the stripping and electrochemical corrosion tests demonstrated that the PDA/PTFE coating has the better stability and anticorrosion ability. The PDA/PTFE coating with the superior properties has potential application for the long-lasting reduction of the scale formation.

Fabrication of stable and versatile superhydrophobic PTFE coating by simple electrodeposition on metal surface

“…The solution temperature was preserved at 5 °C for the electrodeposition process, which lasted 15 minutes at a voltage of 70 V. Cathodic 4 current density for electrodeposition was 1 A•dm −2 .The cathode samples were taken from the solution after electrodeposition and dried naturally at 25 °C in air. After being heated to 372 °C for 4 minutes, the prepared samples were solidified [28] .…”

One‐pot construction of polydopamine‐based superhydrophobic coating with enhanced chemical stability and anti‐fouling performance

“…Recently, polydopamine (PDA) has been receiving immense attention because it can strongly adhere to a variety of substrates, irrespective of smooth or rough substrates under a wet environment. [1][2][3] In 2007, Messersmith et al 4 were inspired by mussel and first carried out selfpolymerization of dopamine (DA) with excellent adhesion properties and the ability of deposition onto various substrates such as metals, [5][6][7] oxides, polymers, 8,9 ceramics even including classically adhesion-resistant materials such as polytetrafluoroethylene (PTFE) 10 under aerobic and alkaline conditions. More importantly, the PDA could be easily further modified by Michael addition and Schiff base reaction due to the large amount of catechol moieties of 3,4-dihydroxy-L-phenylalanine and amino group of lysine on its surfaces.…”

Study on Anti-Scale and Anti-Corrosion of Polydopamine Coating on Metal Surface

“…Scale is a layer of solid or oozy material that gradually accumulates on a solid surface in contact with a fluid. Scale deposition on the surface of pipes and heat exchange equipment is a widespread problem in various industrial fields, which not only leads to the reduction in heat exchange efficiency but results in the corrosion of the equipment's surface, thus causing huge security risks and economic loss [1][2][3][4][5]. In order to reduce the formation and attachment of scale on the surface of equipment, researchers have developed many anti-scale methods, such as scale inhibitors, electric field anti-scale, etc., [6][7][8][9][10], but effective anti-scale measures are still very limited.…”

“…It is worth noting that the PDA coating has excellent corrosion resistance [14]. At present, PDA composite coating is mostly used in scale inhibition [1,[15][16][17], in which PDA mainly plays the role of adhesion and fixation; however, whether PDA coating itself has a scaleinhibition effect is not yet clear. In the traditional chemical preparation process of PDA coating, dopamine polymerization must be induced by adding oxidizer to neutral or acidic water media [18][19][20].…”

“…In addition, the preparation process of PDA will be affected by many factors, such as pH, temperature, reaction time, and so on [21]. For example, Wang et al [1] calibrated the configured Tris buffer pH value as 8.5, mixed it with dopamine solution, then added ammonium persulfate oxidant, and immersed the base in the reaction solution at 50 • C for 6 h to prepare PDA coating. Tris buffer or oxidant components will inevitably be doped into the coating, which may change the physicochemical properties of the coating [21,22].…”