Silylated Carbon Nanofiber/Polydimethylsiloxane Based Printable Electrorheological and Sensor Inks for Flexible...

Area of Science:

• Materials Science
• Rheology
• Nanotechnology

Background:

• Electrorheological fluids (ERFs) offer on-demand actuation.
• Stimuli-responsive printable inks are crucial for flexible electronics.
• A material combining both ERF and printable ink functionalities is highly desirable.

Purpose of the Study:

• To develop a novel printable ink with electrorheological properties.
• To investigate the ink's response to electric fields and temperature.
• To assess the ink's long-term behavior, printability, and sensing capabilities.

Main Methods:

• Formulation of a printable ink using silylated carbon nanofiber (SiCNF)-polydimethylsiloxane (PDMS).
• Rheological characterization under varying electric fields (E) and temperatures.
• Application of time-temperature and time-waiting time superposition principles.
• Direct ink writing for fabricating printed designs.
• Evaluation of pressure sensing performance and stability.

Main Results:

• Ink viscosity increased by 43% under an electric field (E = 300 V mm⁻¹).
• Yield stress (τy) increased by 1600% (E = 600 V mm⁻¹) and was further enhanced by temperature.
• Stable performance over 20 cycles under electric fields.
• Time-temperature and time-waiting time superposition predicted long-term behavior.
• Printed ink demonstrated pressure sensing with 6.3%/kPa sensitivity over 60 cycles.

Conclusions:

• The developed SiCNF-PDMS ink successfully combines electrorheological and printable ink functionalities.
• The ink exhibits significant electrorheological effects and tunable properties with electric fields and temperature.
• The material demonstrates excellent printability and stable pressure sensing capabilities, suitable for flexible electronics.