A simple two-step solution chemistry method for synthesis of micropatterned ZnO nanorods based on metal-loaded hydrogels

High-quality micropatterning of ZnO nanorods was obtained by combining deposition of patterned ZnO seed layers, through soft lithography of metal-loaded hydrogels, with a solution method for growth of nanorods. The embossed hydrogel was photo-polymerised and thermally degraded, providing uniform, well-sintered seed layers with low surface roughness and a film thickness tunable in the range of 50–200 nm. The films were composed of small nanoparticles (20–30 nm) that were fully crystalline and had a preferred orientation along the c axis. These films acted as ideal seed layers for the growth of nanorods, whose diameter could be controlled by the seeding grain size, in the range of 50–100 nm. The procedure yielded complex patterns of dense arrays of vertically aligned nanorods characterised by high lithographic quality, using inexpensive, environmentally-friendly chemicals and simple experimental apparatus.

► Micropatterned ZnO nanorods are obtained by soft-lithography and hydrothermal growth.
► Patterned and thermally degraded hydrogels produce high-quality ZnO seeding films.
► Dense, vertical aligned nanorods arrays are patterned without geometric restrictions.
► The diameter of the nanorods is controlled by tuning the seeding grain size.
► The method is simple, inexpensive and environmentally-friendly.