Distinct Nanopatterns on Dry Etched Semicrystalline Polymer Films Controlled by Mechanical Orientation

Directional dry etching of polymer films under oxygen plasmas combined with a controlled crystallization and mechanical pretreatment of the polymer sample was exploited for obtaining surface nanopatterns. Fibrillar and lamellae surface nanopatterns of different dimensions, either randomly distributed or aligned in a particular direction, were obtained depending on the mechanical history. Similar structures were obtained from iPP and PET if the samples had comparable thermal and mechanical pretreatments. The obtained results are from preferential etching of domains with low order from the surface and persistence of highly ordered ones at low etching ratios. This patterning method seems to be applicable to different polymer materials independently of their chemical composition and can be regarded as a low-cost alternative at the nanoscale to current patterning techniques relying on lithography and replication.