In:
The Journal of Chemical Physics, AIP Publishing, Vol. 124, No. 17 ( 2006-05-07)
Abstract:
Substrates of aluminum (Al) deposited by physical vapor deposition onto Si substrates and then chemically reacted with perfluorodecylphosphonic acid (PFDP∕Al∕Si), decylphosphonic acid (DP∕Al∕Si), and octadecylphosphonic acid (ODP∕Al∕Si) were studied by x-ray photoelectron spectroscopy (XPS), contact angle measurements, atomic force microscopy (AFM), and friction force microscopy, a derivative of AFM, to characterize their surface chemical composition, roughness, and micro-/nanotribological properties. XPS analysis confirmed the presence of perfluorinated and nonperfluorinated alkylphosphonate molecules on the PFDP∕Al∕Si, DP∕Al∕Si, and ODP∕Al∕Si. The sessile drop static contact angle of pure water on PFDP∕Al∕Si was typically more than 130° and on DP∕Al∕Si and ODP∕Al∕Si typically more than 125° indicating that all phosphonic acid reacted Al∕Si samples were very hydrophobic. The surface roughness for PFDP∕Al∕Si, DP∕Al∕Si, ODP∕Al∕Si, and bare Al∕Si was approximately 35nm as determined by AFM. The surface energy for PFDP∕Al∕Si was determined to be approximately 11mN∕m by the Zisman plot method compared to 21 and 20mN∕m for DP∕Al∕Si and ODP∕Al∕Si, respectively. Tribology involves the measure of lateral forces due to friction and adhesion between two surfaces. Friction, adhesion, and wear play important roles in the performance of micro-/nanoelectromechanical systems. PFDP∕Al∕Si gave the lowest adhesion and coefficient of friction values while bare Al∕Si gave the highest. The adhesion and coefficient of friction values for DP∕Al∕Si and ODP∕Al∕Si were comparable.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2006
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
Permalink