Role of surfactant head group and chain length in aqueous lubrication: Steel−steel contact

Abstract

Surfactants are important molecules to decide the lubricating characteristics in aqueous lubrication. In metal working fluids, stabilization of oil droplets in continuous water phase is aided by repulsive force created by surfactants at oilÀwater interface. Present study explores the possibility of participation of surfactants molecules in lubrication process. Effect of surfactant hydrocarbon chain length and type of head group in aqueous lubrication is explored. Aqueous solutions were prepared using Oleic acid, Tween 20 and Tween 80 surfactants. Goniometer was used for recording surface and interfacial effects of surfactants in water and on steel substrate. Lubricating response of aqueous solutions of surfactants was recorded using Tribometer. Ability of a surfactant to adsorb the steel surface along with longer hydrocarbon chain length is well suited for aqueous lubrication. Solubility of surfactant in water is another important parameter.

Surfactant controlled lubricity of paraffin oil-based nano-emulsion

“…The emulsion with smallest droplet size distribution shows higher wettability (Figures 3 and 4) and the difference in surface tension of different emulsions is marginal (Figure 3). Though the difference in contact angles and surface tensions is not very high but Figure 3(b) confirms that these surfactants are capable in modifying the surface [34]. In the present study, the time available for the surfactants to modify the surface is very low, but still some difference is noticed.…”

Generation and stabilization of CO2 nanobubbles using surfactants for extraction of polyphenols from Camellia oleifera shells

“…Additionally, the NBs were shielded from coalescence by surfactant molecules of outer shell and partial surface covering (as illustrated in section 3.7). The adsorption of Tween 80 and Rhamnolipid to bubble was through chemisorption of carboxylic head and electrostatic interaction, respectively (Kumar et al., 2016). In conclusion, the surface tension of stabilized CO 2 ‐NBs by surfactants contributed to the maintenance of the reduced bubble size.…”

“…Based on the method of pendant drop (Kumar et al, 2016), with slight modification to determine the surface tension of CO 2 -NBs solutions including Tween 80 and Rhamnolipid surfactant at 25 ± 1 • C. The CO 2 -NBs solution was stirred at 10 min at 500g on a magnetic stirrer, after which the pendant drops of were suspended on a needle and the surface tension was calculated from the shadow image of a pendant drop using drop shape analysis.…”

Aqueous lubrication and wear properties of nonionic bottle-brush polymers

“…1–3 The aqueous lubricant is a potential for eco-friendly lubricants. 4–7 Economically, water is a comparatively cheaper and richer source than oil, while it is safe and biocompatible. In terms of functionality, it can act as an excellent coolant.…”