Adsorption of fatty acids from alkane solution studied with quartz crystal microbalance

Abstract

This paper describes the adsorption of the unsaturated fatty acids, oleic-, linoleic-, and linolenic acid onto steel coated quartz crystal surfaces from 2,2,4,4,6,8,8-heptamethylnonane as monitored by the quartz crystal microbalance (QCM) technique. It is shown that addition of fatty acid to the oil results in changes in bulk density and viscosity and that these changes must be considered before the sensed mass can be evaluated. The change in viscosity of the solution is larger for oleic acid than for linoleic acid and linolenic acid, which results in a larger correction for oleic acid with respect to bulk effects. After considering the effects due to changes in bulk properties, the influence of the viscoelastic properties of the adsorbed layer on the sensed mass was evaluated. The correction for the viscoelastic properties of the adsorbed layer was found to be very small for the systems studied. The sensed mass, at 1.1 weight percent, ranged from 0.5 mg/m 2 for oleic acid to 5 mg/m 2 for linolenic acid.

Friction Modifier Additives

“…These include the surface forces apparatus (SFA) [58][59][60][61], atomic/lateral force microscope (AFM/LFM) [62][63][64][65], quartz crystal microbalance (QCM) [66], ultrathin film interferometry (UTFI) [67], neutron reflectometry [68,69] and various surface-specific vibrational spectroscopies [70][71][72]. Methods were also developed to generate model close-packed monolayers by chemical grafting of self-assembled alkylthiols and alkyl siloxanes on solid surfaces [73][74].…”

“…SFA has confirmed that saturated alkyl chain OFMs adsorb from solution to form vertically oriented monolayers on mica [59,61] and also cobalt surfaces [58,60] while QCM has shown that oleic acid molecules appear to adsorb parallel to the surface on iron [66]. In AFM/LFM a sphere or sharp tip is rubbed against a substrate to provide a reasonably close analogue of a high pressure sliding asperity contact.…”

Ultralow Friction of a Tetrahedral Amorphous Carbon Film Lubricated with an Environmentally Friendly Ester-Based Oil

“…This relationship is linear as long as the added mass is rigid, firmly attached to the surface, and small compared with that of the crystal. Equation (1) was derived and is known as the Sauerbrey relation [13].…”

“…In this study, the adsorption properties of ester-based oils were evaluated by measuring the changes in resonance frequency(∆f) of quartz-crystal sensors [13]. In addition, the viscoelastic properties of the adsorbed film were evaluated by measuring the dissipation factor (D), which is the inverse of the Q factor and defined by 1 2…”

Tools to Probe Nanoscale Surface Phenomena in Cellulose Thin Films: Applications in the Area of Adsorption and Friction

“…As the thickness, the adsorption mass and structure of the adsorbed layer are crucial to the performance of lubrication (Rabinowi 1967;Grudev and Bondaren 1973;Visscher and Kanters 1990;Gilmour, Paul et al 2002) in situ techniques that can measure these phenomena are needed. Surface Plasmon Resonance (SPR) and Quartz Crystal Microbalance (QCM) are well-established noninvasive methods capable of providing a wealth of information about interfacial phenomena in situ, in real time and in fluid media (Stockbridge 1966;Nomura, Okuhara et al 1981;Nomura and Okuhara 1982;Gordon 1985a, 1985b;Johannsmann, Mathauer et al 1992;Liedberg, Nylander et al 1995;Rodahl, Hook et al 1995;Kasemo 1996a, 1996b;Mak and Krim 1997;Homola, Yee et al 1999;Bailey, Kanazawa et al 2001;Bruschi and Mistura 2001;Bailey, Kambhampati et al 2002;Wang, Mousavi et al 2003;Krim, Abdelmaksoud et al Lundgren, Persson et al 2006). Ellipsometry is another powerful technique that can be applied to measure the mass and thickness of adsorbed layers (Fukuzawa, Shimuta et al 2005).…”