Academic literature on the topic 'Chemomechanical functionalization'

Progress in chemomechanical functionalization was made by investigating the binding of molecules and surface coverage on the silicon surface, demonstrating functionalization of silicon with gases by chemomechanical means, analyzing atomic force microscopy probe tip wear in atomic force microscopy (AFM) chemomechanical nanografting, combining chemomechanical functionalization and nanografting to pattern silicon with an atomic force microscope, and extending chemomechanical nanografting to silicon dioxide. Molecular mechanics of alkenes and alkynes bound to Si(001)-2x1 as a model of chemomechanically functionalized surfaces indicated that complete coverage is energetically favorable and becomes more favorable for longer chain species. Scribing a silicon surface in the presence of ethylene and acetylene demonstrated chemomechanical functionalization with gaseous reagents, which simplifies sample cleanup and adds a range of reagents to those possible for chemomechanical functionalization. Thermal desorption spectroscopy was performed on chemomechanically functionalized samples and demonstrated the similarity in binding of molecules to the scribed silicon surface and to the common Si(001)-2x1 and Si(111)-7x7 surfaces. The wearing of atomic force microscope probe tips during chemomechanical functionalization was investigated by correlating change over time and force with widths of created lines to illustrate the detrimental effect of tip wear on mechanically-driven nanopatterning methods. In order to have a starting surface more stable than hydrogen-terminated silicon, silicon reacted with 1-octene was used as a starting surface for AFM chemomechanical functionalization, producing chemomechanical nanografting. Chemomechanical nanografting was then demonstrated on silicon dioxide using silane molecules; the initial passivating layer reduced the tip friction on the surface to allow only partial nanografting of the silane molecules. These studies broadened the scope and understanding of chemomechanical functionalization and nanografting.

Microelectromechanical chemical and biological sensors have garnered significant interest over the past two decades due to their ability to selectively detect very small amounts of added mass. Today, most resonant mass sensors utilize chemomechanically-induced shifts in the linear natural frequency for detection. In this paper, an alternative, amplitude-based sensing approach, which exploits dynamic transitions across saddle-node bifurcations that exist in a microresonator’s nonlinear frequency response, is investigated. In comparison to their more traditional, linear counterparts, these bifurcation-based sensors have the ability to provide improved sensor metrics, eliminate power-consuming hardware from final sensor implementations, and operate effectively at smaller (e.g. nano) scales. The present work details the ongoing development of a bifurcation-based mass sensor founded upon the near-resonant response of piezoelectrically-actuated microcantilevers. Specifically, the work details the modeling and analysis of these devices, their functionalization, and proof-of-concept mass sensing experiments which not only validate the proposed technique, but allow for the direct evaluation of pertinent sensor metrics.