Enormous-stiffness-changing polymer networks by glass transition mediated microphase separation

Area of Science:

• Materials Science
• Polymer Chemistry
• Soft Robotics

Background:

• Flexible electronics and soft robotics require materials with tunable stiffness.
• Existing materials often lack the wide range of stiffness change needed for advanced applications.

Purpose of the Study:

• To develop a polymer network with switchable stiffness for flexible electronics and soft robotics.
• To achieve a large stiffness change ratio through controlled phase separation and polymer vitrification.

Main Methods:

• Synthesized a polymer network capable of isochoric and reversible stiffness switching.
• Utilized polymer vitrification to regulate liquid-liquid phase separation (Berghmans' point).
• Tuned stiffness change by modifying Lewis acid-base interactions between polymer and ionic liquids.

Main Results:

• Achieved a gigantic stiffness change from ~600 Pa to 85 MPa (ratio > 10^5).
• Demonstrated reversible switching between soft ionogel and rigid plastic states.
• Enhanced interfacial adhesion by an order of magnitude and reduced interfacial impedance by 75%.

Conclusions:

• The developed polymer network offers unprecedented stiffness tunability.
• This material is highly adaptable and reconfigurable, improving performance in electronic interfaces.
• The findings pave the way for next-generation soft robotic and flexible electronic devices.