Citation
Dubey, Manish; Weidner, Tobias; Gamble, Lara J.; & Castner, David G. (2010).
Structure and Order of Phosphonic Acid-Based Self-Assembled Monolayers on Si(100).
Langmuir, 26(18), 14747-14754.
Abstract
Organophosphonic acid self-assembled monolayers (SAMs) on oxide surfaces have recently seen increased use in electrical and biological sensor applications. The reliability and reproducibility of these sensors require good molecular organization in these SAMs. In this regard, packing, order and alignment in the SAMs is important, as it influences the electron transport measurements. In this study, we examine the order of hydroxyl- and methyl- terminated phosphonate films deposited onto silicon oxide surfaces by the tethering by aggregation and growth method using complementary, state-of-art surface characterization tools. Near edge x-ray absorption fine structure (NEXAFS) spectroscopy and in situ sum frequency generation (SFG) spectroscopy are used to study the order of the phosphonate SAMs in vacuum and under aqueous conditions, respectively. X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry results show that these samples form chemically intact monolayer phosphonate films. NEXAFS and SFG spectroscopy showed that molecular order exists in the octadecylphosphonic acid and 11-hydroxyundecylphosphonic acid SAMs. The chain tilt angles in these SAMs were approximately 37° and 45°, respectively.
Reference Type
Journal Article
Secondary Title
Langmuir
Author(s)
Dubey, ManishWeidner, TobiasGamble, Lara J.Castner, David G.
Year Published
2010
Date Published
1285027200
Volume Number
26
Issue Number
18
Pages
14747-14754
DOI
10.1021/la1021438
