A perspective on wearable strain sensors featuring ionogel or eutectogel electrolytes

Area of Science:

• Soft Materials Science
• Electrolyte Chemistry
• Sensor Technology

Background:

• Hydrogels, common gel materials, utilize water-based electrolytes that are prone to evaporation.
• Ionic liquids (ILs) and deep eutectic mixtures (DEMs) are non-aqueous electrolytes offering enhanced stability against evaporation.

Purpose of the Study:

• To explore the development of ionogels and eutectogels as stable, non-evaporating gel materials.
• To investigate the potential of these gels in forming resistive strain sensors.

Main Methods:

• Formulation of ionogels and eutectogels using ILs and DEMs with (co)polymer supports.
• Fabrication of resistive strain sensors by contacting gels with electrodes.
• Analysis of relative ionic resistance change upon axial deformation.

Main Results:

• Ionogels and eutectogels demonstrate resistance to evaporation, unlike traditional hydrogels.
• Resistive strain sensors can be successfully formed using these non-aqueous gels.
• Sensor performance is linked to changes in gel cross-section during deformation.

Conclusions:

• Ionogels and eutectogels represent a promising class of stable, non-evaporating gel materials.
• These gels are suitable for developing advanced resistive strain sensors.
• Future research should focus on enhancing sensor stability, using non-toxic and recyclable materials, and assessing implementation costs.