Soft lithography is a well established technique for efficient low-cost nano patterning of various surfaces on large areas using structured elastomers for pattern transfer.

A commonly used elastomer is polydimethylsiloxane (PDMS) as is eases the applicability in many research areas due to its optical transparency, its non-toxicity and its straight-forward handling. In the ‚microcontact printing‘ approach patterned PDMS can be used for the stamping of nanoparticle- or molecular inks onto surface in patterns.

We investigate the creation of large-area patterned PDMS stamps with nanoscale stamping features by combining soft lithography with nanosphere lithography.

Hexagonally close-packed monolayers of polymer spheres can be deposited from aqueous suspensions onto solid surfaces by means of convective self-assembly, as described in nanosphere lithography. We use these particle layers as topographic template in the PDMS patterning process. We pour the liquid PDMS onto this template and cure the siloxane thermally (see sketch on top). Thus, after release of the stamp from the template, the PDMS is patterned with hexagonally arranged nanotips as the replica of the sphere layer, as shown in the AFM image.