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

Abstract

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 mm 2 to cm 2 .

Structured Ti/Hydrocarbon Plasma Polymer Nanocomposites Produced By Magnetron Sputtering with Glancing Angle Deposition

“…In fact, the only example of fabrication of organic film by evaporative GLAD method was demonstrated by Hrudey et al where highly ordered chiral structures were engineered from tris‐(8‐hydroxyquinoline) aluminum 11. Three‐dimensional helical structures fabricated from acrylate polymers were also reported by Elias et al12 However, in this case, the GLAD was utilized only for deposition of SiO 2 helices, which then served as a master substrate for deposition of intermediate photoresist layer with successive liquid polymer impregnation.…”

Microchannels filled with diverse micro- and nanostructures fabricated by glancing angle deposition

“…gold, nickel) and polymers (e.g. acrylates), 55,61 and these could replace PDMS in the fabrication process.…”

“…The substrate and photoresist were baked for 90 s at 115 C to remove residual solvent and were left to equilibrate to room humidity for more than 30 min. The resist completely infiltrates the GLAD film, 41,55 and an overburden of photoresist typically remains on top of the structures after spinning in the resist, shown schematically in Fig. 1.2.…”

Enhanced power conversion efficiency of quantum dot sensitized solar cells with near single-crystalline TiO_2 nanohelixes used as photoanodes

“…In addition, e-beam evaporation is a well-matured technique compatible with current microelectronics technology, which enables uniform, high-quality deposition of any evaporable materials by a batch process, thus, the capability of large area deposition on multiple wafer (or cell) scale can be achieved by appropriate chamber size and design. Various applications utilizing the advantages of the oblique angle deposition have been demonstrated [49][50][51][52][53]. For fabricating a TiO 2 nanohelix array, the substrate was tilted against vapor flux at 80°, and repeated rotation with a speed of 1rpm for 2 seconds followed by a pause for 12 seconds; the film deposition rate was 5Å/s.…”