Renewable Superhydrophobic Surfaces Prepared by Nanoimprinting Using Anodic Porous Alumina Molds

Abstract

Renewable superhydrophobic surfaces based on laminated polymer films with nanopillar array structures were prepared. Polymer nanopillar arrays exhibiting superhydrophobic properties were prepared by nanoimprinting using anodic porous alumina as a mold. The hydrophobic properties of the obtained polymer nanopillar arrays could be controlled and optimized by changing the geometrical structures of anodic porous alumina molds used for nanoimprinting. The polymer films were laminated using a photocurable monomer. The ordered polymer nanopillar array structures could be maintained even after delamination of the films. Renewed polymer nanopillar arrays exposed by peeling off the upper films exhibited a water contact angle higher than 150°. Using this process, superhydrophobic surfaces could be obtained repeatedly by delamination of a film even when superhydrophobicity deteriorated with the collapse of surface patterns. The obtained renewable superhydrophobic surfaces can be used for various applications requiring high durability.

Preparation of Polymer Nanopillar Arrays with Controlled Tip Shapes and Their Application to Hydrophobic and Oleophobic Surfaces

“…These results show good correspondence to our previously reported results of water droplet contact angle measurements using polymer nanopillar arrays with a 200−500 nm period. 30 On the other hand, when n-hexadecane, which has low surface tension, was used, the contact angle decreased as the period of the nanopillars increased. This is considered to be due to the fact that in a solution with low surface tension, if the gap between nanopillars becomes too large, droplets sink into the gap and surfaces become wet easily, resulting in a low contact angle.…”

“…In our previous report, we showed that optimization of the diameter of nanopillars and interpillar distances could generate surfaces that exhibit superhydrophobic properties exceeding 150°. 30 We also reported that the formation of micro-/nanohierarchical structures by combining micrometer-scale struc- tures in the nanopillar array structures could generate superhydrophobic surfaces with a contact angle of over 170°. 29,31,32 However, in our previous studies, the tip shape of polymer nanopillars was limited to a hemispherical shape corresponding to the pore shape of anodic porous alumina, and the effect of the nanopillar tip shape on water-and oil-repellent properties has not yet been investigated.…”

Nanopillar Polymer Films as Antibacterial Packaging Materials

“…The transfer was performed at atmospheric pressure for 60s at room temperature (RT). After pattern transfer, the acrylic was cured under UV irradiation (1 J/cm 2 at 365 nm wavelength) in nitrogen atmosphere, as previously described. − Delamination of the films was carried out by manual peeling.…”

Wrinkled Interfaces: Taking Advantage of Anisotropic Wrinkling to Periodically Pattern Polymer Surfaces

“…Besides specific periods require the synthesis of specialized compounds. [ 13 , 14 , 15 , 16 , 17 ] The latter adopts traditional techniques, such as micromolding (embossing) [ 18 , 19 , 20 , 21 , 22 ] or micro/nanoimprinting, [ 23 , 24 , 25 , 26 ] and/or by developing novel techniques with higher resolution capabilities including laser‐induced periodic surface structure, [ 27 , 28 ] soft lithography, [ 29 , 30 , 31 , 32 ] or direct laser interference patterning, [ 33 , 34 ] among others. Technological advances offer unparalleled versatility and fidelity.…”