In this work, we performed a systematic study on the effect of the geometry of pre-patterned templates and spin-coating conditions on the self-assembling process of colloidal nanospheres. To achieve this goal, large-scale templates, with different size and shape, were generated by direct laser-writer lithography over square millimetre areas. When deposited over patterned templates, the ordering dynamics of the self-assembled nanospheres exhibits an inverse trend with respect to that observed for the maximisation of the correlation length xi on a flat surface. Furthermore, the self-assembly process was found to be strongly dependent on the height (H) of the template sidewalls. In particular, we observed that, when H is 0.6 times the nanospheres diameter and spinning speed 2500 rpm, the formation of a confined and well ordered monolayer is promoted. To unveil the defects generation inside the templates, a systematic assessment of the directed self-assembly quality was performed by a novel method based on Delaunay triangulation. As a result of this study, we found that, in the best deposition conditions, the self-assembly process leads to well-ordered monolayer that extended for tens of micrometres within the linear templates, where 96.2% of them is aligned with the template sidewalls.
Directed self-assembly of polystyrene nanospheres by direct laser-writing lithography / Cara, Eleonora; Ferrarese Lupi, Federico; Fretto, Matteo; De Leo, Natascia; Tortello, Mauro; Gonnelli, Renato; Sparnacci, Katia; Boarino, Luca. - In: NANOMATERIALS. - ISSN 2079-4991. - ELETTRONICO. - 10:2(2020), p. 280. [10.3390/nano10020280]
|Titolo:||Directed self-assembly of polystyrene nanospheres by direct laser-writing lithography|
|Data di pubblicazione:||2020|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.3390/nano10020280|
|Appare nelle tipologie:||1.1 Articolo in rivista|