Adhesion properties and surface analyses of monolayers ofn-dodecanethiol self-assembled on galvanic gold

✍ Scribed by Noël, Sophie; Bodin, Camille; Boyer, Lionel; Houzé, Frédéric; Mekhalif, Zineb; Delhalle, Joseph; Pireaux, Jean-Jacques

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 165 KB
• Volume: 26
• Category: Article
• ISSN: 0142-2421
• DOI: 10.1002/(sici)1096-9918(199811)26:12<889::aid-sia431>3.0.co;2-u

✦ Synopsis

Galvanic gold is an important protective Ðnal layer in most low-level electrical contacts for high-reliability applications. Despite the chemical inertia of gold, it is widely admitted that adding an organic layer (polyphenyl esters, perÑuorinated polyethers) to such surfaces minimizes friction and wear during insertion and extraction operations, as well as prevents corrosion.

In a recently published work on nickel surfaces we have shown that a single monolayer of mercaptan exhibits outstanding antifriction and antiwear properties. Here we report the Ðrst results an adhesion, friction and spectroscopic characteristics of n-dodecanethiol monolayers built on galvanic gold.

Based on several works showing the relation between adhesion and friction, we study two parameters : the static friction coefficient at the onset of sliding, and the dynamic friction coefficient during motion. The system used to conduct the study is a ball (CuBe)-plane (CuZn) set-up where both the ball and the underlying metallic plane have a Ðnal electrodeposited gold layer (¿2 lm). Two types of modiÐcation of the gold-Ðnished plane by ndodecanethiol are compared : direct immersion of the surface as received, and immersion of the surface after UV-ozone exposure. Results of the adhesion and friction experiments are correlated with detailed XPS surface analyses of the modiÐed surfaces with n-dodecanethiol.