title: Phase separation of a mixed self-assembled monolayer prepared via a stepwise method.
abstract: Self-assembled monolayers (SAMs), a molecular-level assembly that forms spontaneously, provide a vehicle for investigating specific interactions at interfaces. This is particularly true for mixed SAMs that are composed of organosilanes with different chain lengths and/or chemical functionalities because they offer an adjustable surface for constructing 3D structures containing a variety of moieties. We recently observed that coadsorbed monolayers with different organosilanes on a Si wafer were separated into several tens or hundreds of nanometer domains that were rich in individual components. Several organosilanes, such as octadecyltrichlorosilane (OTS), octadecyltrimethoxysilane (OTMS), (3-mercaptopropyl)trimethoxysilane (MPTMS), and (3-aminopropryl)trimethoxysilane (APTMS), were used for regional separation. In this study, we propose a stepwise deposition method, namely, the deposition of a second siliane on a SAM substrate that creates intentional defects in the first silane. The surface morphologies were adjusted by the deposition sequence and immersion time of the silanes. As a result, a mixed SAM prepared by the proposed method showed effectively functionalized films compared to that prepared by the one-step method.
authors.affiliation: School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Kwanak, Seoul 151-742, Korea.
authors.forename: Inhee
authors.initials: I
authors.lastname: Choi
authors.forename: Younghun
authors.initials: Y
authors.lastname: Kim
authors.forename: Sung Koo
authors.initials: SK
authors.lastname: Kang
authors.forename: Jeongjin
authors.initials: J
authors.lastname: Lee
authors.forename: Jongheop
authors.initials: J
authors.lastname: Yi
mesh_terms: D006046:Gold; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D015394:Molecular Structure; D053758:Nanoparticles / Q000648:ultrastructure; D012821:Silanes / Q000737:chemistry* / Q000302:isolation & purification*; D014867:Water / Q000737:chemistry
chemical_list: D012821:Silanes; D014867:Water; D006046:Gold