Anisotropic Superhydrophobic Properties Replicated from Leek Leaves

Area of Science:

• Materials Science
• Surface Science
• Bio-inspired Engineering

Background:

• Superhydrophobic (SHB) surfaces offer unique wetting properties.
• Natural structures, like leek leaves, provide templates for advanced material design.
• Anisotropic properties are desirable for specialized surface functionalities.

Purpose of the Study:

• To fabricate robust SHB surfaces with anisotropic properties using a bio-inspired approach.
• To replicate the microgroove structure and epicuticular wax mimicry of leek leaves.
• To evaluate the wetting, anti-icing, and optical properties of the fabricated surfaces.

Main Methods:

• Fabrication of polydimethylsiloxane (PDMS) replicas from leek leaf microgrooves.
• Coating PDMS replicas with a modified candle soot (CS) layer to mimic epicuticular wax.
• Characterization of surface wettability (contact angle), durability (bending, abrasion), ice adhesion, transmittance, and haze.

Main Results:

• Replicated surfaces exhibited anisotropic wetting with a contact angle difference of ≈30° along different directions.
• The CS-coated replicas demonstrated excellent durability against cyclic bending and sand abrasion.
• Low ice adhesion (10 kPa) was observed, with anisotropy in adhesion increasing after multiple icing-shearing cycles.
• The CS-coated positive replica showed significant light transmittance (≈73%) and haze (≈65%) at 550 nm.

Conclusions:

• Leek leaves serve as an effective template for creating bio-inspired surfaces with anisotropic properties.
• The fabricated SHB surfaces possess robust anti-icing and desirable optical characteristics.
• This bio-inspired method offers a promising route for developing advanced functional materials.