Structural Variations and Ordering Conditions for the Self-Assembled Monolayers of HS(CH2CH2O)(3-6)CH3

Published

April 29, 2003

Author(s)

David J. Vanderah, J Arsenault, H La, Richard S. Gates, Vitalii I. Silin, Curtis W. Meuse, Gintaras Valincius

Abstract

The structure and ordering conditions of the self-assembled monolayers (SAMs) of HS(EO)xR, where R = CH3, EO = CH2CH2O, and x = 3 to 6, on polycrystalline gold (Au) were determined by reflection adsorption infrared spectroscopy (RAIRS), spectroscopic ellipsometry (SE), and electrochemical impedance spectroscopy (EIS). For x = 5 and 6, RAIRS and SE data show that the 1-thiaoligo(ethylene oxide) [TOEO] segments adopt the highly ordered 7/2 helical structure of the folded-chain crystal polymorph of crystalline poly(ethylene oxide) and are oriented normal to the substrate. RAIRS and SE data obtained as function of immersion time show that x = 6 attains the highly ordered, all helical conformation between 20 and 24 times faster than x = 5. For x = 3 and 4, RAIRS and SE data indicate largely disordered structures, with some all-trans conformation but little evidence of the helical conformation. Specific capacitance values, from EIS measurements in an aqueous environment, generally follow expected trends and indicate a significant presence of water in all SAMs x

Citation

Langmuir

Volume

19

Issue

9

Pub Type

Journals

Keywords

electrochemical impedance spectroscopy, oligo(ethylene oxides), reflection-absorption infrared spectrosc, self-assembled monolayers

Citation

Ross, D. , Arsenault, J. , La, H. , Gates, R. , Silin, V. , Meuse, C. and Valincius, G. (2003), Structural Variations and Ordering Conditions for the Self-Assembled Monolayers of HS(CH2CH2O)(3-6)CH3, Langmuir (Accessed March 13, 2025)