Open the Pores: Particles with Fully Accessible Hierarchical Pore Networks by Controlling Phase Separation in...

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Hierarchical porous materials offer high surface area and efficient mass transport.
• Producing accessible macropores and mesopores in bulk is challenging.
• Emulsion droplet synthesis often results in pore-blocking silica shells.

Purpose of the Study:

• To develop a method for creating hierarchical porous particles with accessible pore systems.
• To overcome the limitation of dense silica shell formation in emulsion droplet synthesis.
• To control interfacial energies to achieve open pore structures.

Main Methods:

• Utilizing polymerization-induced spinodal decomposition of poly(ethylene glycol) and tetraethyl orthosilicate.
• Employing surfactant mixtures to tune interfacial energies and induce neutral wetting.
• Conducting Lattice Boltzmann simulations to validate experimental findings.

Main Results:

• Neutral wetting conditions (contact angle ~90°) prevent shell formation.
• Generated hierarchical porous particles with fully open, interconnected pore systems.
• Achieved controlled porosity ranging from approximately 200 to 6000 nm.

Conclusions:

• Controlling interfacial energies via surfactant mixtures is a key strategy for producing accessible hierarchical porous particles.
• Neutral wetting is essential for eliminating pore-blocking surface shells.
• The developed method expands the potential of hierarchical porous materials in catalysis, separation, and adsorption.