Thickness and scratch resistance of adsorbed film formed by triblock symmetrical copolymer solutions

Abstract

The thickness and scratch resistance of adsorbed films formed on mild steel samples (MS1020), which have been immersed in water copolymer solutions, are reported. The effects of bulk temperature and the copolymer structures, normal, poly(ethylene oxide)m‐poly(propylene oxide)n‐poly(ethylene oxide)m, and reverse, poly(propylene oxide)n‐poly(ethylene oxide)m‐poly(propylene oxide)n, are elucidated. The films' thicknesses are independent of structure but not of temperature. The adsorbed films of above cloud point solutions are thicker than below cloud point. However, nanoscratch experiments carried out to measure the scratch resistance of the films reveal that despite of thicker film formed by above cloud point solutions, it is relatively more prone to being detached than the thinner films of below cloud point solutions. The effect of extreme pressure additive, alkyl phosphate ester (APE), is also investigated suggesting the normal copolymer has comparable scratch resistance with APE when used at below the cloud point. Copyright © 2016 John Wiley & Sons, Ltd.

Influence of molecular structure on lubrication of aqueous triblock copolymer lubricants between rutile surfaces: An MD approach

“…Additionally, this theoretical investigation also aims to support previous experimental studies [1,15,19,20,35]. An MD model has been developed to simulate realistically the self-assembled molecular structure of adsorbed Pluronics at the atomic scale.…”

Surface Film Adsorption and Lubricity of Soybean Oil In-Water Emulsion and Triblock Copolymer Aqueous Solution: A Comparative Study

“…It is clearly demonstrated that the adsorbed copolymer layer can be removed from the surface by means of a simple surface cleaning process ( Figure 13 left) while those lubricated by the VO/W emulsions still have residue on the surface (Figure 13 right). While vegetable oils tendency to produce ROOH hydroperoxide through oxidation results in thickening, varnish formation and sludge deposition on surfaces [26,63] and postulates poor cleanability, triblock copolymers have high wetting and spreading ability, thus are easily rinsed with Milli-Q water [8,20]. This direct observation, together with the QCM film removal of Figures 3 and 4 at rinsing stage (above 20 min) demonstrates the superior surface cleanability of the copolymer solutions compared to the VO/W emulsions, albeit with higher friction and wear.…”

“…This makes vegetable oil in water emulsion a cost effective green and renewable lubricant with low oil consumption, in accordance with the minimum quantity lubricant MQL strategy [18,19]. Aqueous triblock copolymer solutions are another class of low cost aqueous alternatives, possessing comparable tribological performance to conventional lubricants and excellent surface cleanability [8,20,21]. …”

“…Water based lubricants are low cost environmentally-friendly substitutes for mineral oil based lubricants. Two types of water based lubricants namely oil in water O/W emulsions [2][3][4][5][6] and aqueous copolymer solutions [7][8][9][10] have been studied.…”

Hydroxyl Influence on Adsorption and Lubrication of an Ultrathin Aqueous Triblock Copolymer Lubricant

“…A standard stainless steel (SS) and TiO 2 -coated SS surfaces, which are partly hydrophobic, 7,8 were chosen in recent experimental studies. 6,8,10,11 In a theoretical approach using molecular dynamics (MD) simulations, nascent iron and pure titanium oxide surfaces were used to relate to the experimental findings on these surfaces.…”