Composite elastomers with on-demand convertible phase separations achieve large and healable electro-actuation

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Phase separation is crucial for functional materials, but structures are typically fixed after fabrication.
• Existing methods lack dynamic control over phase morphology throughout a material's lifespan.

Purpose of the Study:

• To develop a strategy for on-demand, reversible phase switching in composite elastomers.
• To engineer materials with tunable nanostructures for enhanced performance and self-healing capabilities.

Main Methods:

• Super-saturating an elastomer matrix with a small-molecule organic compound (SMOC) to induce nanophase separation.
• Utilizing temperature changes to control transitions between homogeneous, nano-, and macro-phase separated states.
• Investigating the role of elastic recovery and SMOC migration for structural reconfiguration and surface localization.

Main Results:

• Achieved reversible switching between homogeneous, nano-, and macro-phase separation states.
• Demonstrated SMOC nanoparticles enhance elastomer network and enable large actuation strains (~146%) by mitigating electro-mechanical instability.
• Showcased on-demand self-healing of dielectric elastomer actuators via SMOC migration to breakdown sites.

Conclusions:

• The developed strategy enables dynamic control over material microstructure, leading to advanced functional properties.
• Reversible phase switching offers a novel pathway for designing high-performance, self-healing dielectric elastomers.
• The in situ formation and dynamic behavior of SMOC nanoparticles are key to achieving superior electro-actuation and repair capabilities.