Large-area microfabrication of three-dimensional, helical polymer structures

A technique has been developed to fabricate polymeric helices with sub-micron dimensions. These helices are made using a double-templating process, in which an inorganic thin film deposited using glancing angle deposition acts as the master. The shape, pitch, handedness and number of turns of the polymer helices can be tuned by altering the deposition parameters of the master film. The structure of this positive master is copied into a negative intermediate template of photoresist, which itself acts as a master for the templating of polymer helices. This process is demonstrated with four multifunctional acrylates. The master, intermediate template and polymer helices are characterized using scanning electron microscopy, and the polymer helices are characterized using energy dispersive x-ray spectroscopy. It is shown that a large number of polymer helical microstructures, which are anchored to both a thick substrate and a thin capping layer, can be made in parallel over areas of mm2 to cm2.