The Influence of Packing Densities and Surface Order on the Frictional Properties of Alkanethiol Self-Assembled Monolayers (SAMs) on Gold: A Comparison of SAMs Derived from Normal and Spiroalkanedithiols
نویسندگان
چکیده
We report a comparative study of the structure and frictional properties of self-assembled monolayers (SAMs) generated by the adsorption of three homologous 17-carbon alkanethiolssheptadecanethiol, 2,2dipentadecyl-1,3-propanedithiol, and 2-pentadecyl-1,3-propanedithiolsonto the surface of Au(111). The structural properties of these SAMs were characterized by atomic force microscopy, surface infrared spectroscopy, X-ray photoelectron spectroscopy, spectral ellipsometry, and wettability by water and hexadecane. The frictional properties of the SAMs were examined by friction force microscopy. The results demonstrate that the packing density and the related crystalline order of the hydrocarbon chains influence the frictional properties of organic thin films. The origins of the frictional differences measured from these films are discussed in terms of the structure of the films.
منابع مشابه
Self-Assembled Monolayers of Azobenzene-Incorporated Alkanethiol on Silver
In the past decade, self-assembled monolayers (SAMs) have received a great deal of attention for their fundamental importance in understanding interfacial properties as well as for their potential applications in molecular technologies. SAMs have been used in the design of various interfaces for chemical sensors, nonlinear optical materials, optical switches, and high density memory devices. Th...
متن کاملSystematic control of the packing density of self-assembled monolayers using bidentate and tridentate chelating alkanethiols.
The structural and interfacial properties of self-assembled monolayers (SAMs) on gold derived from the adsorption of a series of 1,1,1-tris(mercaptomethyl)alkanes (i.e., CH3(CH2)mC[CH2SH]3, where m = 9, 11, 13, 15) were investigated. The new SAMs, which possess uniformly low densities of alkyl chains, were characterized by ellipsometry, contact angle goniometry, and polarization modulation infr...
متن کاملSelf-Assembled Monolayers Generated from Unsymmetrical Partially Fluorinated Spiroalkanedithiols.
Self-assembled monolayers (SAMs) were prepared on gold substrates from an unsymmetrical partially fluorinated spiroalkanedithiol adsorbate with the specific structure of [CH3(CH2)7][CF3(CF2)7(CH2)8]C[CH2SH]2 (SADT) and compared to SAMs formed from the semifluorinated monothiol F8H10SH [CF3(CF2)7(CH2)10SH] of analogous chain length and n-octadecanethiol. The adsorbate with two alkyl chains, one ...
متن کاملMolecular Packing of Semifluorinated Alkanethiol Self-Assembled Monolayers on Gold: Influence of Alkyl Spacer Length
The structures of semifluorinated alkanethiol self-assembled monolayers (SAMs) generated by the adsorption of CF3(CF2)9(CH2)nSH (F10HnSH, n ) 2, 6, 11, 17, 33) onto gold were investigated with atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and surface plasmon resonance spectroscopy. Images obtained by AFM of the F10H2SH SAM showed a remarkably ordered 2D hexagonal lattic...
متن کاملFormation of highly ordered self-assembled monolayers of alkynes on Au(111) substrate.
Self-assembled monolayers (SAMs), prepared by reaction of terminal n-alkynes (HC≡C(CH2)nCH3, n = 5, 7, 9, and 11) with Au(111) at 60 °C were characterized using scanning tunneling microscopy (STM), infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS), and contact angles of water. In contrast to previous spectroscopic studies of this type of SAMs, these com...
متن کامل