Mapping Orientation Differences of Terminal Functional Groups by Friction Force Microscopy

The Porter-Whitesides Discrepancy: Revisiting Odd-Even Effects in Wetting Properties of n-Alkanethiolate SAMs

“…Wong et al studied the tribology between the SAMs (CH3(CH2)nS-Au (n = 12-16)) and a bare probe tip using friction force microscopy (FFM) [16]. They observed an odd-even alternation in the friction force, depending on the odd or even number of CH2 units in the molecular chain.…”

“…Favorable secondary interaction between the methylene hydrogens leads to better packing and ordered assemblies; (iii) The terminal functional group provides a platform where any desired group can be introduced to alter the chemical nature of the interface. The ability to symmetrically alter the moieties in the head and tail groups makes SAMs excellent systems for fundamental understanding of phenomena dependent on competing intermolecular, molecular-substrates, and, molecule-solvent interactions; for example friction, wetting, adhesion, lubrication, and corrosion [5][6][7][15][16][17][18][19][20].…”

Construction of Various Self-assembled Films and Their Application as Lubricant Coatings

“…The spatial orientation of the tail groups also has a prominent impact on adhesion and friction. For example, an "odd-even" effect is observed for SAMs with same tail groups but different CH 2 number (odd or even) in the alkyl chain (Chang et al, 1994;Lee et al, 2001;Smith & Porter, 1993;Tao, 1993;Wong et al, 1998). As shown in Fig.…”

Electrochemical and scanning probe microscopic characterization of spontaneously adsorbed organothiolate monolayers at gold

“…Several laboratories [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], including our own [18][19][20][21][22], have described a variety of interesting aspects about the reductive resorption and oxidative deposition for alkanethiolates chemisorbed at gold electrodes (i.e., Equation 1). We have found, for example, that the X(CH2).S-AU + e-# X(CH2),S-+ Au (1) resorption process at smooth electrodes (i.e., annealed mica-supported gold) reflects the presence of thiolates bound on the terrace sites of Au(l 11) [21].…”

“…Many studies have been conducted to characterize the monolayer with different chemistry in the organic spacer [6] and the endgroup regions [7][8][9][10][11][12][13][14][15][16]. The techniques used to probe the monolayer architectures vary widely.…”