Self-assembled mesoporous silica nanoparticles in controlled patterns produced by soft-lithography and ink-jet printing.

This study demonstrate assembly of mesoporous silica nanoparticles (MSNs) into various patterns by soft-lithography and ink-jet printing techniques. A clear suspension containing MSNs with a particle size around 58 nm is firstly synthesized. Then, soft-lithographic techniques (i.e., MIMIC, impression with PDMS) and an ink-jet printing technique are applied to create various patterns assembled by MSNs. The MIMIC method results in a high density of MSNs, but is limited to linear patterns due to the capillary principle. The impression method led to MSN colloids in various patterns, but the MSNs assembled in low density due to the lack of the colloidal supplements. The ink-jet technique can create various patterns more conveniently, and the final patterns are generated after a de-wetting process. During the de-wetting process, the MSN concentrations and the jetted times are related only to the final number of particles dispersed in patterns. Comparison of different patterning techniques will be helpful towards creation of patterned assembly with MSNs.