Fabrication of large-area hierarchical structure array using siliconized-silsesquioxane as a nanoscale etching barrier.

A Material approach to fabricate a large-area hierarchical structure array is presented. The replica Molding and oxygen (O-2) plasma etching processes, were combined to fabricate a large-area hierarchical: structure array. Liquid blends consisting of siliconized silsesquioxane acrylate (Si-SSQA), ethylene glycol dimethacrylate (EGDMA), and photoinitiator are developed as a Toughness amplifying material during O-2 plasma :etching: Microstructures composed Of the Si-SSQA/EGDMA mixtures are fabricated: by replica molding. Nanoscale toughness on molded microstructures is realized by O-2 etching. The nanoscale roughness, on microstructure is efficiently controlled by varying the etching time and the weight ratio of Si-SSQA to EGDMA. The hierarchical structures fabricated by combining, replica molding and O-2 plasma etching showed superhydrophilicity with long-term stability, resulting in the formation of hydroxyl-terminated oxide layer with the reorientation limit. On the other hand, the hierarchical structures. modified with a perfluorinated monolayer showed superhydrophobicity. The increment of water contact angles is consistent with increment of the nano/microroughness of hierarchical structures and decrement of the top contact area of water/hierarchical structures.