Langmuir, Vol.24, No.3, 826-829, 2008
Self-assembled monolayers of an oligo(ethylene oxide) disulfide and its corresponding thiol assembled from water: Characterization and protein resistance
Self-assembled monolayers (SAMs) of the disulfide [S(C(H)2CH(2)O)(6)CH3](2) ([S(EO)(6)](2)) on An from 95% ethanol and from 100% water are described. Spectroscopic ellipsometry and reflection-absorption infrared spectroscopy indicate that the [S(EO)(6)](2) films are similar to the disordered films of HS(CH2CH2O)(6)CH3 ((EO)(6)) and HS(CH2)(3)O(CH2-CH2O)(5)CH3 (C3EO5) at their protein adsorption minima. The [S(EO)(6)](2) SAMs exhibit constant film thickness (d) of 1.2 +/- 0.2 nm over long immersion times (up to 20 days) and do not attain the highly ordered, 7/2 helical structure of the (EO)(6) and C3EO5 SAMs (d = 2.0 nm). Exposure of these self-limiting [S(EO)(6)](2) SAMs to bovine serum albumin show high resistance to protein adsorption.