Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.Includes bibliographical references (leaf 24).A study of the behavior of nanoparticles in the presence of solvent vapors is presented. Millimeter-scale films of gold nanoparticles, one nanometer thick, are treated with solvent vapors at various temperatures and the behavior of the nanoparticles is tracked over time using transmission electron microscopy. The ultimate goal of this processing is to repair defects such as grains, dislocations, and vacancies in the original superlattice. Additionally, Langmuir-Schaeffer films of gold nanoparticles on water surfaces are subjected to thermal and ultrasonic treatment in an attempt to correct defects in the films, which are then transferred to solid substrates for observation. Unfortunately, none of these approaches is able to reduce the defect concentration in a lattice, although thermal treatment and sonication of Langmuir-Schaeffer nanoparticle films are found to provide a controllable approach to depositing exact double layers of nanoparticles.by Vladimir Tarasov.S.B