Colliding autocatalytic wave-fronts of organosilane (OS) layer self-assembly are generated through the controlled positioning of sources of the volatile OS material at the edges of a silica wafer and through adjustment of the container dimensions in which the wafer-source system is placed. The concentration profiles and molecular orientation of the OSs of colliding wave-fronts are assessed by means of combinatorial near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. For systems involving waves made of the same OS precursor (homogeneous systems), the shapes and positions of both fronts on the surface are centro-symmetrical. In contrast, heterogeneous systems, involving OSs having different chemistries and head-groups, exhibit highly non-symmetrical concentration profiles on the substrate. We discuss effects relevant to understanding these wave-front collision phenomena.
Citation: Soft Matter Gradient Surfaces: Methods & Applications
Publisher Info: Wiley, New York, NY
Pub Type: Books
fluctuation-induced interfacial broadening, frontal self-assembly, mean-field Fisher Kolmogorov equation, reaction diffusion fronts, self-assembled monolayers