Reversible superhydrophilicity and superhydrophobicity on a lotus-leaf pattern

Area of Science:

• Materials Science
• Surface Chemistry
• Polymer Science

Background:

• Superhydrophobic and superhydrophilic surfaces mimic natural phenomena like the lotus leaf effect.
• Controlling surface wettability is crucial for applications in self-cleaning, anti-fouling, and microfluidics.
• Developing stimuli-responsive materials that can dynamically alter their surface properties remains a significant challenge.

Purpose of the Study:

• To present a facile method for creating a temperature-responsive coating with reversible superhydrophobic-to-superhydrophilic switching.
• To investigate the role of surface roughness and tunable surface energy in achieving switchable wettability.
• To demonstrate a biomimetic approach that not only replicates but also enhances natural surface properties.

Main Methods:

• Fabrication of the coating involved a combination of micromolding, layer-by-layer assembly of polymer macroinitiators, and surface-initiated polymerization.
• Surface roughness was introduced by replicating the micro/nanostructure of a lotus leaf surface using micromolding.
• Temperature-responsive polymer brushes were grafted onto the surface to enable dynamic switching of surface energy levels.

Main Results:

• The developed coating demonstrated reversible switching between superhydrophobic and superhydrophilic states in response to temperature changes.
• Wetting studies confirmed the significant influence of surface roughness and the temperature-induced changes in surface energy on wettability.
• The approach successfully replicated the lotus leaf's surface morphology and introduced tunable, stimulus-responsive wetting behavior.

Conclusions:

• A facile and effective method for fabricating temperature-responsive coatings with switchable wettability has been established.
• The combination of biomimetic surface roughness and grafted polymer brushes provides a robust platform for creating advanced smart surfaces.
• This work offers a promising strategy for designing materials with dynamic surface properties for diverse technological applications.