Embedded Core-Shell 3D Printing (eCS3DP) with Low-Viscosity Polysiloxanes.

Area of Science:

• Materials Science
• Additive Manufacturing
• Soft Robotics

Background:

• Flexible 3D structures are crucial for soft sensors and actuators.
• Fabricating 3D objects with internal architectures using liquid precursors is challenging due to structural instability, especially with low-viscosity resins.

Purpose of the Study:

• To present a novel three-phase system for direct ink writing (DIW) 3D printing of flexible core-shell structures.
• To overcome the limitations of fabricating 3D objects with internal channels using low-viscosity resins.

Main Methods:

• Utilized direct ink writing (DIW) in a three-phase system.
• Employed a core-shell printing approach with a low-viscosity polysiloxane resin (Ecoflex 10) as shell ink and Pluronic F127 in an ethanol gel as core ink.
• Investigated the rheological properties of the three fluids to ensure filament stability.

Main Results:

• Developed embedded core-shell 3D printing (eCS3DP) capable of fabricating stable core-shell filaments.
• Achieved suppression of interfacial instability by using a high concentration of Pluronic F127 (30 w/w%) in the core liquid.
• Successfully fabricated perfusable channels by removing the core liquid and demonstrated lateral attachment of printed filaments.
• Observed the formation of core liquid droplets along printed filaments through controlled rheological properties and flow rates.

Conclusions:

• eCS3DP provides a straightforward method for creating 3D soft elastomeric structures with embedded channels.
• This technique is a valuable tool for DIW-based fabrication of flexible wearable devices and soft robotic components.