Single monolayers of octadecylcarboxylic acids (C18) and octacosanoic acids (C28) and mixed monolayers with ratios of 75%-25%, 50%-50%, and 25%-75% were formed spontaneously on the [0001] basal surface of α-aluminum oxide (single crystalline sapphire) using solution deposition methods. The binding nature and hydrophobicity of the monolayers were analyzed via diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and water contact angle measurements, respectively. Atomic force microscopy (AFM) was employed to investigate frictional properties of the monolayers in addition to acquisition of surface topography. DRIFT spectra confirmed the formation of highly ordered monolayers with mono/bidentate binding. Water contact angles indicated hydrophobic nature of single monolayers and mixed monolayers. The degree of hydrophobicity increased as the composition of C28 increased. Topographic and friction images demonstrated that the mixed monolayers form less frictional islands of C28 surrounded by the physically lower and highly frictional C18 layer.

Nano-tribological properties of single monolayers and mixed monolayers of octadecylcarboxylic acid and octacosanoic acid

253rd National Meeting (2017)

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