Novel fatty acid anion-based ionic liquids: Contact angle, surface tension, polarity fraction and spreading parameter

Abstract

This work deals with the determination of several wetting properties (contact angle, surface tension, polarity fraction and spreading parameter) of six novel fatty acid anion-based ionic liquids (FAILs): methyltrioctylammonium hexanoate [N 8881 ][C 6:0 ], methyltrioctylammonium octanoate [N 8881 ][C 8:0 ], methyltrioctylammonium laurate [N 8881 ][C 12:0 ], methyltrioctylammonium palmitate [N 8881 ][C 16:0 ], methyltrioctylammonium stearate [N 8881 ][C 18:0 ] and methyltrioctylammonium oleate [N 8881 ][C 18:1 ]. Surface tension was determined at temperatures from 293 to 333 K, exhibiting a linear decrease within the temperature range. Contact angle measurements were performed on five different surfaces (steel, aluminum, tungsten carbide, cast iron and bronze) using 3 test liquids (water, diiodomethane and ethylenglycol)and each of the synthesized FAILs. Polarity fraction (PF) and the spreading parameter (SP) were calculated in order to gain a deeper understanding of wetting characteristics of these FAILs. Despite the similarity of the obtained results with all FAILs and surfaces, [N 8881 ][C 6:0 ] and [N 8881 ][C 8:0 ] with both cast iron and bronze surfaces were the best surface-FAIL combinations regarding wettability.

Two fatty acid anion-based ionic liquids - part I: Physicochemical properties and tribological behavior as neat lubricants

“…However, both properties decrease in this research with the increase of the alkyl chain length of the anion, similarly to other FAILs employed in previous research works [64][65][66][67]. The differences in viscosity behavior could be explained in a similar way that what happen with surface tension [46]. The alkyl chain interactions seem to have a major contribution to the viscosity while the polar groups of the FAILs seem to have a reduced influence.…”

“…Although natural oils are largely used as lubricants since the beginning of lubrication, utilisation of biobased lubricants is rising [40][41][42][43][44][45][46]. The enormous possibilities of synthetizing ILs through the combination of existing ions lead to the obtention of new environmentally friendly compounds that improve biodegradability and non-toxic characteristics contributing to a more sustainable development [47].…”

Relationships between the physical properties and biodegradability and bacteria toxicity of fatty acid-based ionic liquids

“…The fatty acid-based ionic liquids (FAILs) were synthesized by means of a salt metathesis reaction according to Battez et al [31]. The details related to their identification through 1 H and 13 C NMR and FTIR analyses can also be found in Battez et al [31] and Blanco et al [32]. Methyltrioctylammonium bromide ionic liquid ( 97%) was employed as cation precursor and natural fatty acids: hexanoic ( 98%), octanoic ( 98%), lauric ( 98%), palmitic ( 98%), stearic ( 98%) and oleic ( 95%) acids were used as anion precursors.…”

Surface energy evaluation of casting and nanofiber polyurethane films by using different models

“…When θ is small, the work of adhesion is high and therefore more energy is necessary to separate the solid from the liquid. 7 The spreading coefficient (S) can be also calculated as the difference between the adhesion (W a ) and cohesion (W c ) work 32,33 :…”

“…The difference between the adhesion (W a ) and cohesion (W c ) work leads to calculation of S. Generally, when S > 0, the liquid will spread spontaneously over the solid in order to lower its surface energy. 33 If, on the other hand, S < 0, the liquid remains in droplet form and partially wet the surface. 9,53 The values of S for the PU samples were negative for all tested liquids.…”