Universal Strain Energy-Mediated Dynamic Porosity in Physically Networked Elastomers and Their Applications

Area of Science:

• Materials Science
• Polymer Science
• Mechanics of Materials

Background:

• Porous polymer properties are typically static and depend on pore structure.
• Existing methods lack dynamic control over pore arrangement after synthesis.

Purpose of the Study:

• To introduce a novel dynamic porosity strategy for physically networked elastomer polymers.
• To demonstrate reversible pore reconfiguration in response to mechanical deformations.

Main Methods:

• Applied mechanical deformations (e.g., finger pressure, compression, stretch) to elastomer films.
• Utilized a strain energy-mediated thermodynamic model to analyze pore behavior.
• Investigated the relationship between pore-to-pore distance and pore reversion pressure.

Main Results:

• Achieved omnidirectional and reversible porosity reconfiguration at ambient conditions.
• Demonstrated a porous-to-solid transition with a 3-order magnitude reduction in pore density and 22% volumetric shrinkage.
• Observed an opaque-to-transparent transition indicating porosity state changes.
• Showcased reversible porosity transitions with coupled compression and in-plane stretch (700%).

Conclusions:

• The dynamic porosity strategy offers unprecedented control over elastomer properties.
• The pore reversion pressure is tunable via pore-to-pore distance control.
• Applications include pressure indication, tunable material characteristics, and flexible photomasks.