3D Micropatterned Surface Inspired by Salvinia molesta via Direct Laser Lithography

Abstract

Biomimetic functional surfaces are attracting increasing attention for their relevant technological applications. Despite these efforts, inherent limitations of microfabrication techniques prevent the replication of complex hierarchical microstructures. Using a 3D laser lithography technique, we fabricated a 3D patterned surface bioinspired to Salvinia molesta leaves. The artificial hairs, with crownlike heads, were reproduced by scaling down (ca. 100 times smaller) the dimensions of natural features, so that microscale hairs with submicrometric resolution were attained. The micropatterned surface, in analogy with the natural model, shows interesting properties in terms of hydrophobicity and air retention when submerged by water, even if realized with a hydrophilic material. Furthermore, we successfully demonstrated the capability to promote localized condensation of water droplets from moisture in the atmosphere.

Superhydrophobic hierarchically structured surfaces in biology: evolution, structural principles and biomimetic applications

“…Persistent air layers under water (Salvinia effect) are discussed in [14,15,[53][54][55][56][57][58][59][60][61][62].…”

“…Search machines like 'Google' provided (May 2016) some 600 000 hits for 'lotus effect' and some 520 000 hits for 'superhydrophobic'. [7], (b) from [62].…”

“…Plasma etching and related techniques enable the fabrication of simple 'rough' surfaces in hydrophobic materials (overview in [178]). In contrast, three-dimensional lithographic methods allow highly complex architectures with complex undercuts like in the replica of the Salvinia trichomes (figure 34b) by Tricinci et al [62]. The self-assembly techniques are unsurpassed.…”

Nanostructure and Microstructure Fabrication: From Desired Properties to Suitable Processes

“…The structures were written in an epoxy‐based resist, using DLW. Reproduced with permission . Copyright 2015, American Chemical Society.…”

Fabrication of a superhydrophobic surface with underwater air-retaining properties by electrostatic flocking

“…Bhushan proved that a structure can be created in the lab to mimic the behavior of salvinia; Sung's research indicated that the air-retaining properties can be greatly enhanced using the salvinia structure compared to the lotus one. Tricinci et al 22 used a 3D laser lithography technique to fabricate a 3D patterned surface bio-inspired by salvinia and the sample showed interesting properties of hydrophobicity and air retention when submerged under water. Holscher et al 23,24 fabricated a nanofur by a hot pulling method to mimic the salvinia effect cost-effectively.…”