Network Formation, Properties, and Actuation Performance of Functionalized Liquid Isoprene Rubber

Area of Science:

• Materials Science
• Polymer Chemistry
• Actuator Technology

Background:

• Liquid rubbers are versatile for dielectric elastomer actuators (DEAs) due to their favorable properties and processability.
• DEAs find applications in automation, automotive, and medical industries.
• Conventional silicone-based elastomers have limitations in performance.

Purpose of the Study:

• To develop a novel cross-linkable liquid rubber composition for enhanced DEA performance.
• To investigate the network formation and material properties of a new isoprene-based elastomer.
• To evaluate the actuation capabilities of the developed elastomer in a dot actuator configuration.

Main Methods:

• Formulation of a cross-linkable liquid rubber using anhydride functional isoprene rubber, carboxyl-terminated nitrile-butadiene rubber, and epoxy end-capped prepolymers.
• Amine-catalyzed esterification for network formation.
• Characterization using HR-MAS NMR spectroscopy, elastic modulus measurement, and dielectric constant determination.
• Fabrication and testing of a dot actuator with the developed isoprene elastomer film.

Main Results:

• Successful formation of an intricate network structure verified by HR-MAS NMR.
• The new isoprene elastomer exhibits a low elastic modulus (0.45 MPa) and high deformability (300%).
• A higher dielectric constant (2.6) compared to conventional silicone elastomers (2.2).
• The fabricated dot actuator demonstrated a significantly higher electrode deformation (0.63%) than commercial silicone films (∼0.30%) at 5 kV.

Conclusions:

• The developed isoprene-based liquid rubber is a promising material for high-performance dielectric elastomer actuators.
• The enhanced actuation performance is attributed to the combination of a low elastic modulus and a high dielectric constant.
• This new material offers potential for improved functionality in various DEA applications.