A Computing Method to Determine the Performance of an Ionic Liquid Gel Soft Actuator.

Area of Science:

• Materials Science
• Robotics
• Polymer Chemistry

Background:

• Ionic liquid gels (ILGs) are emerging as promising soft actuator materials.
• Understanding the mechanical properties of ILGs is crucial for their application in soft robotics.
• Hyperelastic theory provides a framework for describing the mechanical behavior of soft materials.

Purpose of the Study:

• To propose and validate the applicability of the Mooney-Rivlin model for characterizing ionic liquid gels (ILGs).
• To develop formulas for calculating stress in ILGs under various tensile conditions using the Mooney-Rivlin model.
• To assess the predictive accuracy of the five-parameter and nine-parameter Mooney-Rivlin models for ILG mechanical response.

Main Methods:

• Synthesis of an ionic liquid gel (ILG) composed of BMIMBF4, HEMA, DEAP, and ZrO2 via UV light irradiation.
• Application of hyperelastic theory and deduction of stress calculation formulas based on five-parameter and nine-parameter Mooney-Rivlin models.
• Uniaxial tensile testing of ILG with 3 wt% ZrO2 to obtain model parameters and experimental stress-strain data.

Main Results:

• The five-parameter Mooney-Rivlin model demonstrated high accuracy, with calculated uniaxial tensile stress deviating by less than 0.51% from experimental data.
• The nine-parameter Mooney-Rivlin model showed a maximum error of 8.87% in predicting uniaxial tensile stress.
• Formulas for uniaxial tensile stress, plane uniform tensile stress, and 3D directional stress were successfully derived for ILGs.

Conclusions:

• The Mooney-Rivlin model, particularly the five-parameter version, provides a feasible and credible method for calculating the stress of ionic liquid gels (ILGs).
• This research establishes a new approach for evaluating the performance of ILG-based soft actuators.
• The findings contribute to the optimized design and development of advanced soft robots utilizing ILG materials.