"Foam Marble" Stabilized with One Type of Polymer Particle

Area of Science:

• Colloid and Surface Science
• Materials Science

Background:

• Colloidal particles at the air-water interface stabilize foams and liquid marbles.
• Particle wettability dictates the type of air/water dispersed system formed.
• Hydrophilic particles typically stabilize foams, while hydrophobic particles stabilize liquid marbles.

Purpose of the Study:

• To demonstrate submicrometer-sized polystyrene particles with poly(N,N-diethylaminoethyl methacrylate) hairs (PDEA-PS particles) as stabilizers for both aqueous foams and liquid marbles.
• To investigate the role of particle wetting modes in stabilizing these systems.
• To create a novel air-in-water-in-air multiple gas-liquid dispersed system, termed "foam marble".

Main Methods:

• Synthesis of PDEA-PS particles via dispersion polymerization.
• Adsorption of PDEA-PS particle flocculates at the air-water interface in a Wenzel mode for foam stabilization.
• Adsorption of dried PDEA-PS particles as aggregates in a metastable Cassie-Baxter mode for liquid marble stabilization.

Main Results:

• PDEA-PS particles successfully stabilize both aqueous foams and liquid marbles, challenging conventional wettability requirements.
• Stabilization of a unique "foam marble" system by exploiting different wetting modes.
• Formation of porous spheres with dual-scale porosity after water evaporation from foam marbles.

Conclusions:

• Hydrophilic PDEA-PS particles can act as versatile stabilizers for diverse gas-liquid systems.
• The wetting mode of particles is crucial for controlling the stabilization mechanism.
• Foam marbles represent a novel platform for creating hierarchical porous materials.