Introducing surface functionality on thermoformed polymeric films

We present a fabrication process for the production of 3-dimensional micro-structured polymeric films. The microstructures are fabricated in a single step using thermal nanoimprint lithography as patterning technique. The micro-structured polymer films are then transformed into a 3D shape by means of a plug-assisted thermoforming process, while keeping the functionality of the micro-patterned areas. The preserved functionality is characterized by water contact angle measurements, while the deformation of the micro-structured topographies due to the thermoforming process is analyzed using confocal microscopy and Digital Image Correlation (DIC) techniques. This combined fabrication process represents a promising solution to complement in-mold decoration approaches, enabling the production of new functional surfaces. As the microstructures are fabricated by means of a mechanical modification of the surface, without the need of chemical treatments or coatings, the presented technique represents a promising, simple and green solution, suitable for the industrial fabrication of 3D nonplanar shaped functional surfaces.