Cost-effective, large-area, reusable nanoimprint molds for polymer nanostructures

In this paper, we report the use of a heptadeca-fluoro-1,1,2,2 tetrahydrodecyl trichlorosilane (HDFS)-coated anodic aluminum oxide (AAO) template as a low-cost, large-area, reusable nanoimprint mold. Coating AAO with HDFS increases the water contact angle (CA) from 20° on a pristine AAO to 120° on an HDFS-coated AAO, thus lowering adhesion of the AAO mold. Nanostructured polydimethylsiloxane (PDMS) could then be easily obtained by using the direct imprinting method on HDFS-coated AAO without any external loads. After nanoimprinting with an HDFS-coated AAO mold, the CA of the mold rarely changes (120° to 115°), thus demonstrating the possibility of a reusable AAO mold. The CA of PDMS increases up to ~15° after nanoimprinting, and its transmittance decreases by 5 ~ 30%, compared with that of a flat PDMS film, in the full visible range due to the scattering effect, which implies that the optical pathway of incident light could be extended in the nanostructured polymer. Therefore, our nanoimprinting method is expected to enable a variety of applications in next-generation soft optoelectronics.