Tailoring and Characterizing Surface Properties

Molecules and nanomaterials can be assembled on surfaces in order to build complex structures and devices from the “bottom up”. To serve as the foundation for these architectures, surfaces are patterned via microcontact printing, a process that directs the adsorption of self assembled monolayers. Microcontact printing uses a polydimethylsiloxane stamp in a process analogous to the use of a rubber stamp. We have developed a protocol to mold stamps from surfaces generated by traditional lithographic techniques. Patterned self assembled monolayers can direct the assembly of metallic nanoparticles, as well as the nucleation of calcium carbonate crystals. Self assembled monolayers can be characterized by contact angle goniometry, a technique which looks at the angle of a drop of solvent on the surface. The contact angle is dependent on the intermolecular interaction between the solvent and the surface allowing the surface energy to be calculated. Information about the surface energy as well as wettability can be utilized to indicate the quality of a self assembled monolayer as well as its’ surface reactivity. Scanning electron microscopy is also used to characterize chemical patterns as well as the assembly and nucleation of particles. We hope to use these assembly and characterization techniques to assemble nanowires into more complex structures