ENGINEERING CONTROLLED FOLDING IN ELECTROACTIVE POLYMERS IN RESPONSE TO AN ELECTRIC FIELD

Open Access
Author:
Hong, Jonathan
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Zoubeida Ounaies , Thesis Supervisor
  • Jacqueline O'Connor , Honors Advisor
Keywords:
  • Electroactive Polymers
  • Smart Materials
  • P(VDF-TrFE-CTFE)
  • Soft Robotics
  • Optimization
Abstract:
This project explores the effects of various unimorph configurations on the folding potential of electroactive polymer actuators. Electroactive polymers convert an electrical input to a mechanical output. The material studied in this project is P(VDF-TrFE-CTFE) terpolymer, or terpolymer for short. Actuating the terpolymer with an electric field creates expansion in the planar direction and a contraction in the thickness direction. Restricting the terpolymer’s expansion with a passive substrate such as scotch tape results in a bending actuator. This bending can be transformed into folding by introducing multiple layers of passive substrate with local stress concentrations; for example, notches are one way to introduce these local stress concentrations. A notch is created by layering patches of passive substrates to create stiffness contrast in the folding actuator. The stiffness contrast creates areas of localized bending which turns into folding for the overall actuator. The size and location of the notches, and the Young’s modulus and thickness of the passive substrate material are systematically investigated to assess the actuator’s folding potential. Experimentally measured folding angles recorded for each configuration will allow for the impact of each parameter to be observed individually. Finally, a terpolymer based gripping device is introduced to demonstrate a possible application of the material. This research will provide experimental data for verifying future finite element analysis models of P(VDF-TrFE-CTFE). Also, unimorph configurations with the highest folding potentials will be selected for future research with terpolymer based actuators.