Preparation and tribological tests of thin fluoroorganic films

• Published in: Applied surface science 2008-05, Vol.254 (14), p.4273-4278
• Main Authors: Cichomski, M., Grobelny, J., Celichowski, G.
• Format: Article
• Language: English
• Subjects: AFM; Atomic, molecular, and ion beam impact and interactions with surfaces; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Fluorosilanes; Impact phenomena (including electron spectra and sputtering); Materials science; Mechanical and acoustical properties; adhesion; Methods of deposition of films and coatings; film growth and epitaxy; Microtribology; Nanotribology; Physics; SAMs; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); ToF-SIMS
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2008.01.008

Adhesion, friction and consequent wear of sliding surfaces are the basic problems that limit the performance and reliability of microelectromechanical devices. Lubrication of these nano- and microscale contacts is different from traditional lubricants. Self-assembled monolayers (SAMs) chemically bonded to the substrate are considered to be the best solution of lubrication. The majority of these monolayers are hydrophobic providing low friction, adhesion and wear. Chemical vapor deposition was used to grow a fluorosilane film on silicon Si(1 0 0) and a condensed monolayer of 3-mercaptopropyltrimethoxysilane (MPTMS) on Au(1 1 1). The films were characterized by means of a contact angle analyzer for hydrophobicity, and time-of-flight secondary ion mass spectrometry (ToF-SIMS) for identification of thin fluoroorganic monolayers deposited on silica surfaces and condensed monolayer MPTMS. Adhesion and friction measurements were performed using atomic force microscopy (AFM) and compared with measurements performed using a microtribometer operating in millinewton (mN) normal load range. Nanotribological measurements indicated that silica and MPTMS modified by fluorosilanes have the lowest friction coefficient and indicated a decrease friction coefficient with increasing fluoric alkyl chain length.