Enhancing electromechanical responsiveness of PVC gels via ion size control

Area of Science:

• Materials Science
• Polymer Science
• Electrochemistry

Background:

• Soft electroactive polymers, like plasticized poly(vinyl chloride) (PVC) gels, are crucial for soft robotics and biomedical applications due to their deformability and rapid response.
• PVC/dibutyl adipate (PVC/DBA) gels show notable bending under low electric fields, but their performance can be further optimized.

Purpose of the Study:

• To enhance the electromechanical response of PVC/DBA gels by incorporating salts with controlled ion sizes.
• To investigate the effect of different ionic liquids and lithium salts on gel properties and performance.

Main Methods:

• Rheological measurements were used to determine gelation concentration and fractal dimension.
• Electrical conductivity and elasticity were measured for gels with and without salt additives.
• Anode-directed bending deformation was quantified under a DC electric field.

Main Results:

• A critical gelation concentration of PVC was found to be w = 0.013 with a fractal dimension of 1.88.
• Salt addition increased electrical conductivity fivefold without significantly altering elasticity in post-gel states (w = 0.143).
• Gels with specific salt combinations (small anion, large cation) exhibited over five times greater bending deformation compared to salt-free gels.

Conclusions:

• Controlled ion size of added salts is an effective strategy to enhance electromechanical performance of PVC/DBA gels.
• Optimized salt selection, particularly ionic liquids with specific ion sizes, can significantly improve bending in response to low electric fields.
• These findings offer a pathway for developing advanced soft electroactive materials for various applications.