Electric fields on gibbsite nanoplatelet assemblies, nanopyramid SERS substrates and graphene actuators.

摘要

This dissertation focuses on the exertion of electric fields to assemble gibbsite nanoplatelets along with various polymers to mimic the intricate brick-and-mortar nanostructure found in abalone shells. A simple electrophoretic (co-)deposition technology that enables rapid production of large-area polymer nanocomposites with layered structures was studied. Addition of binders and assembling of surface-roughened gibbsite nanoplatelets were also studied. The tensile strength and the stiffness of these biomimetic nanocomposites were significantly improved when compared to pure polymer films.;The exertion of electric fields to conduct electrochemical SERS on nanostructured substrates that were templated from self-assembled colloidal silica arrays as well as to drive graphene-based actuators that were made by flow-directed assembly of one-atom-thick graphene sheets were also studied. Periodic arrays of nanopyramids with nanoscale sharp tips and high tip density demonstrated an enhancement on the order of 106. Actuations of a graphene actuator operated by cyclic voltammetry at a scan rate of 50 mV/s were able to last up to 140 cycles without significant degradation.