Abstract

We present the synthesis and characterization of novel phenolic surfactants 12,12'-disulfanediylbis(dodecane-12,1-diyl) bis(3,4,5-trihydroxybenzoate) and 12-mercaptododecyl 4-hydroxybenzoate. These molecules combine the phenolic functionality of tannins found in nature with self-assembly and organizational properties of surfactants. The surfactants consist of a (C12) hydrophobic, ω-thiol or disulphide functionality: both commonly used anchors in self-assembly onto gold surfaces. Our modular synthetic route addressed the purification challenges often encountered by using acetyl protecting. Our synthetic strategy unraveled sodium thiomethoxide’s ability of unmasking the thiol moiety and simultaneously deprotecting acetyl protecting groups in the presence of an internal ester. This provides an efficient procedure that can be used to synthesize similar surfactants. The synthesized surfactants were studied at the air-water interface by plotting isotherms that showed the thiol and disulfide group had a significant effect at air-water interface. Lower collapse pressure was obtained for thiolated or disulfide surfactant in comparison with the surfactant to its non-thiolated equivalent. We present Langmuir-Schaefer deposition and mixed monolayer as to produce films with varied density by depositing at different pressure. Controlling monolayer density and optimizing the spacing requirement for the interaction of phenol head group with for example proline rich proteins.