Printable polymer actuators from ionic liquid, soluble polyimide, and ubiquitous carbon materials.

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• High-performance polymer actuators require electrolytes with excellent ionic conductivity and mechanical integrity.
• Ionic liquids (ILs) and soluble polyimides (SPI) are promising components for advanced polymer electrolytes.

Purpose of the Study:

• To develop printable, high-performance polymer actuators utilizing ionic liquid-based polymer electrolytes and various carbon materials.
• To investigate the influence of different carbon electrode compositions on actuator performance, including displacement, response speed, and durability.

Main Methods:

• Fabrication of polymer electrolytes using sulfonated polyimide (SPI) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C2mim][NTf2]).
• Preparation of polymer actuators with a trilaminar structure using SPI/[C2mim][NTf2] electrolytes and carbon electrodes (activated carbon, acetylene black, vapor grown carbon fiber, Ketjen black).
• Characterization of electrolyte properties (ionic conductivity, elastic modulus) and actuator performance (displacement, response speed, durability, generated force).

Main Results:

• The SPI/[C2mim][NTf2] electrolytes achieved ionic conductivity of 1 × 10(-3) S cm(-1) and an elastic modulus >1 × 10(7) Pa.
• Actuators with mixed activated carbon/Ketjen black electrodes showed large displacement, high-speed response, and retained 80% of initial displacement after 5000 cycles.
• Actuator displacement was found to be proportional to accumulated electric charge, consistent with existing models.

Conclusions:

• Printable, high-performance polymer actuators can be fabricated using ionic liquid-based polymer electrolytes and carefully selected carbon materials.
• The combination of carbon electrodes significantly impacts actuator performance, with AC/KB mixtures offering a balance of displacement, speed, and durability.
• The study provides a viable pathway for developing advanced polymer actuators for various applications.