pH-Responsive Shape Memory Porous Foam for Intelligent On-Demand Separation of Various Oil-Water Systems

Area of Science:

• Materials Science
• Polymer Chemistry
• Separation Technology

Background:

• Existing intelligent superwettability materials for oil-water separation face limitations in response dimensionality, surface modification durability, and on-demand capabilities.
• There is a need for advanced materials that offer multi-functional, controllable, and robust solutions for complex separation challenges.

Purpose of the Study:

• To develop an intelligent material with dual-regulated surface wettability and pore size for advanced oil-water separation.
• To overcome the limitations of current superwettability materials by introducing pH-responsiveness and shape memory properties.

Main Methods:

• Fabrication of a porous double-regulated foam (DRF) by combining epoxy resin with a pH-responsive polymer (PMMA-co-PDEAEMA) using a salt template method.
• Utilizing pH changes (acidic/alkaline) to modulate surface wettability between hydrophobic/oleophilic and hydrophilic/oleophobic states.
• Employing temperature changes (130 °C) to induce shape memory effects, reversibly altering pore size from 150 μm down to nanoscale.

Main Results:

• The developed DRF30 material demonstrated reversible switching of wettability and controllable pore size reduction.
• Achieved high separation flux (>1300 L m⁻² h⁻¹) for oil-water mixtures in the uncompressed state and high efficiency (>99.5%) for emulsions in the compressed state.
• The material exhibited excellent durability and physicochemical stability over multiple separation cycles.

Conclusions:

• The novel strategy of combining pH-responsive polymers and shape memory materials offers a promising approach for intelligent, on-demand oil-water separation.
• The DRF material presents a significant advancement in smart material design for efficient and adaptable separation applications.
• This work provides valuable insights for developing next-generation materials with tunable properties for environmental and industrial uses.