STED-Inspired Nanolithography beyond (Meth-)Acrylates

1) Wider research context The project is embedded in the wider research context of sub-diffractional, three-dimensional optical lithography, inspired by STED microscopy (Nobel prize 2014). 2) Objectives With some rare exceptions, STED-inspired nanolithography is restricted so far to (meth)acrylates. It is the objective of this proposal to transfer STED-inspired lithography to other polymers, comprising epoxides and conductive polymers, potentially allowing for nanoscale, sensitive electrochemical organic field effect transistors (OFETs) and, on the long run, fast organic nanoelectronics. 3) Methods The core methods comprise STED-inspired lithography and the search for optically depletable photoinitiators for cationic and oxidative photo-polymerization reactions. 4) Level of innovation Expanding STED inspired lithography to cationic or oxidative polymerization is absolutely innovative in the field. For the latter, not a single publication exists, for the former, there is a sole prior publication from the Klar Group. Working on cationic and oxidative polymerizations in STED-inspired lithography needs substantially more original ideas for depletion strategies compared to free radical polymerization of acrylates. The latter required comparatively simplistic single component, type II photoinitiators which are photo-depletable, such as thioxanthones or ketocoumarins. Already for ordinary two-photon cationic polymerization, two-component sensitizer/initiator systems are required. 5) Primary researchers involved The primary researcher, Thomas A. Klar constructed the first ever working STED microscope and is now one of the world leaders in transferring this technology to optical lithography. The Klar Group is the first in the world who recently managed to apply STED-inspired lithography to cationic polymers.