Porous Layer-by-Layer Films Assembled Using Polyelectrolyte Blend to Control Wetting Properties

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Layer-by-layer (LbL) films are used for superwetting surfaces.
• Existing LbL films are limited to two oppositely charged polyelectrolytes.
• Controlling surface morphology is key for advanced material properties.

Purpose of the Study:

• To develop novel porous LbL films with tunable surface morphologies.
• To investigate the effect of polymer blends and acid treatment on film properties.
• To assess the superwetting and slippery surface capabilities of the fabricated films.

Main Methods:

• Assembling LbL films using a cationic polymer blend (branched poly(ethylene imine) (BPEI) and poly(allylamine hydrochloride) (PAH)) and anionic poly(acrylic acid).
• Acid-treating the LbL films at pH 1.8-2.0 to induce porosity.
• Coating the porous films with fluorinated silane and infusing with lubricant oil.

Main Results:

• Varying BPEI/PAH ratios in LbL films resulted in diverse surface morphologies.
• Fluorinated films with 50% PAH achieved high water contact angles (140-150°).
• The fabricated surfaces exhibited low water (10-20°) and oil (5-10°) sliding angles, with BPEI/PAH blends showing superior performance.

Conclusions:

• Acid treatment of blended polyelectrolyte LbL films effectively controls surface morphology.
• The developed porous films demonstrate significant potential for superwetting and slippery surface applications.
• This approach offers a versatile method for designing advanced functional surfaces.