Formation of nanometer domains of one chemical functionality in a continuous matrix of a second chemical functionality by sequential adsorption of silane self-assembled monolayers

In this paper, we describe a procedure to prepare mixed self-assembled mono layers containing nanometer to micrometer domains of a chemical functionali ty surrounded by another chemical functionality, using sequential adsorptio n. Partial monolayers of octadecyltrichlorosilane (OTS) consisting of conde nsed islands with controlled size are prepared by varying the deposition co nditions. The area surrounding the OTS islands is backfilled with 11-bromo undecyltrichlorosilane (BrUTS) or decyltrichlorosilane (DTS) to obtain nano meter to micrometer scale domains of OTS in a monolayer of DTS or BrUTS. Fi rst, we describe in detail the methodology to form partial OTS monolayers c omposed of domains of a desired size. Then, we discuss the procedure and op timum conditions for successful backfilling. These monolayers were analyzed by atomic force microscopy (AFM) to obtain height and friction images in c ontact and tapping modes. In addition, we have studied (1) the friction pro perties of various phases in OTS monolayers, (2) the morphology of monolaye rs on silicon substrates with various degrees of hydration, and (3) in situ adsorption of OTS monolayers using AFM.