Squeeze-out of branched alkanes on graphite.
نویسندگان
چکیده
We study squalane and heptamethylnonane (HMN) confined between a conducting atomic force microscope tip and a graphite surface. Solvation layering occurs for both liquids but marked differences in the squeeze out mechanics are observed for ordered or disordered monolayers. The squalane monolayer at 25 degrees C is an ordered solid, as verified by direct imaging, and the squeeze out can be modeled using elastic continuum mechanics. HMN is in a disordered state at 25 degrees C and cannot be modeled as a single elastic asperity even in solid-solid contact because HMN liquid is trapped in the contact zone.
منابع مشابه
Epicuticular Wax Alkanes of Scutellaria Lateriflora L. Leaves
The dried aerial parts of scutellaria lateriflora L. (family Labiatae), have been used for many years as a domestic remedy for epilepsy, hysteria, and nervous tension states. Although several phytochemical investigations have been made regarding the constituents present in this species (i. e. flavonoids, iridoids), none has been recorded concerning the cuticular wax. Using thin-layer chroma...
متن کاملOrdering of liquid squalane near a solid surface
X-ray reflectivity is used to study the interfacial structure of liquid squalane on SiO2/Si(1 0 0) substrates. The data show that there are density oscillations ( layers ) near the interface, with the squalane molecular long axes parallel to the substrate. The results are compared to those from molecular dynamics simulations and recent force measurements. 2005 Elsevier B.V. All rights reserved....
متن کاملSurface tensions of linear and branched alkanes from Monte Carlo simulations using the anisotropic united atom model.
The anisotropic united atoms (AUA4) model has been used for linear and branched alkanes to predict the surface tension as a function of temperature by Monte Carlo simulations. Simulations are carried out for n-alkanes ( n-C5, n-C6, n-C7, and n-C10) and for two branched C7 isomers (2,3-dimethylpentane and 2,4-dimethylpentane). Different operational expressions of the surface tension using both t...
متن کاملSelf-assembly of long chain alkanes and their derivatives on graphite.
We combine scanning tunneling microscopy (STM) measurements with ab initio calculations to study the self-assembly of long chain alkanes and related alcohol and carboxylic acid molecules on graphite. For each system, we identify the optimum adsorption geometry and explain the energetic origin of the domain formation observed in the STM images. Our results for the hierarchy of adsorbate-adsorbat...
متن کاملProtolytic decomposition of n-octane on graphite at near room temperature
Graphite basal surface is inert, and decomposition of n-alkanes on the graphite surface has not been discovered. We here report the evidence of decomposition of n-octanes on highly oriented pyrolytic graphite (HOPG) surface, heat-treated up to 1200 °C under high vacuum (10(-7) Pa), at near room temperatures. Using a temperature programmed desorption apparatus equipped with a quadrupole mass spe...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review letters
دوره 100 7 شماره
صفحات -
تاریخ انتشار 2008