Desorption Kinetics and Energetics of Monodisperse Fomblin Zdol from Carbon Surfaces

Abstract

Desorption is one of the mechanisms of lubricant loss from the surfaces of data storage media. This work has studied the desorption of monodisperse samples of a typical perfluoropolyalkyl ether lubricant, Fomblin Zdol, from the surface of graphite. Desorption is observed to occur molecularly through a first-order process with an energy barrier to desorption, ∆E des ‡ , that is independent of coverage but is dependent on molecular weight. The ∆E des ‡ of 994 and 1329 g/mole fractions were found to be 128 ( 2 kJ/mol and 155 ( 2 kJ/mol, respectively. The pre-exponents, V, of the first-order desorption rate constant were found to have values of 10 19.6(0.3 s -1 and 10 21.1(0.3 s -1 for the 994 and 1329 g/mole Zdol fractions, respectively. These results clearly reveal the chain length dependence of the ∆E des ‡ , and the high values of the pre-exponents are similar to those observed for desorption of other oligomeric species from graphite.

The Influence of Ultraviolet Irradiation on the Surface Chemistry of Ztetraol Magnetic Hard Disk Lubricant: a Combined Temperature Programed Desorption and X-Ray Photoelectron Spectroscopic Study

“…Each model results in the formation of reactive fragments that are capable of interacting further and in the case of the released CF 2 O would directly decrease the relative amount of methylene in the irradiated film. Furthermore, Model 3 contains a fragment terminated with a CFO moiety, which has a facile chemistry with atmospheric water to yield an acid end group that can readily increase the surface COO -concentration as observed with XPS [40].…”

Carbon nanotubes grown by catalytic CO2 laser-induced chemical vapor deposition on core-shell Fe/C composite nanoparticles

“…It was shown that at temperatures below 1000°C, a non-oxidative thermal treatment may evaporate some PAHs while others could undergo chemical conversion by different mechanisms such as reaction with light gas species, loss of C 2 -units followed by reaction with a PAH and dimerization [28]. At temperatures in the 500-800 K range a competition between desorption/ evaporation and decomposition of high molecular weight organic molecules at a carbon graphite surface was observed [29,30].…”

Synthesis and properties of cyclotriphosphazene and perfluoropolyether‐based lubricant with polar functional groups

“…Enhancement of lubricant mobility can be achieved by designing a lubricant either with a relatively low molecular weight or with low intermolecular interaction, which may cause low viscosity. However, these types of lubricants usually have a relatively high volatility and subsequently result in fast evaporative loss during a long term usage . Low bonding of lubricant on the disk surface is another issue which could cause loss of lubricant and finally result in disk damage .…”

“…However, these types of lubricants usually have a relatively high volatility and subsequently result in fast evaporative loss during a long term usage. 2 Low bonding of lubricant on the disk surface is another issue which could cause loss of lubricant and finally result in disk damage. 3 Therefore, a moderate mobility of lubricant is preferably required to provide excellent wear durability in the hard disk media.…”