Structural Variations and Ordering Conditions for the Self-Assembled Monolayers of HS(CH2CH2O)(3-6)CH3
David J. Vanderah, J Arsenault, H La, Richard S. Gates, Vitalii I. Silin, Curtis W. Meuse, Gintaras Valincius
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
, Arsenault, J.
, La, H.
, Gates, R.
, Silin, V.
, Meuse, C.
and Valincius, G.
Structural Variations and Ordering Conditions for the Self-Assembled Monolayers of HS(CH2CH2O)(3-6)CH3, Langmuir
(Accessed June 7, 2023)