Assembly of highly-ordered structures for nanosphere lithography

Student thesis: Master thesis (including HD thesis)

  • Sergio Fernandez Martinez
4. term, Nanotechnology, Master (Master Programme)
Nanosphere lithography has attracted the attention of researches as an alternative for the high equipment costs of conventional lithography by the combination of bottom-up and bottom-down approaches. The high throughput and large-area fabrication depend on the self-assembled monolayer which acts as a colloidal mask. For this reason, the aim of this thesis is to explore different methods for preparation of a colloidal crystal monolayer made of nano-and microspheres.
Self-assembled monolayers of silica nanospheres via Droplet evaporation were not successfully formed in neither hydrophobic nor hydrophilic substrates. The aggregation forces were dominant during the arrangement process with an insufficient lateral capillary force to enhance order.
On the contrary, polystyrene particles via Droplet method displayed large areas of hexagonal close-packing together with vacancies and defect lines. Dip-coating method also provided highly-ordered monolayers regarding the arrangement extension with a strong influence in the suspension concentration, solvents and withdrawal speed indicating that coating conditions could be further optimized. The monolayers formed at the air/water interface via Langmuir-Blodgett method resulted in better order for micro-polystyrene particles with domains of hexagonal packing as well as line defects. The main drawbacks were the compression stability during monolayer transfer and the material loss into the subphase influenced by the dispersion solvent and the hydrophilicity of the poly(acrylic acid) grafted on the polystyrene surface.
Publication date15 Jul 2016
Number of pages141
ID: 238521224