On-demand modulation of 3D-printed elastomers using programmable droplet inclusions.

Area of Science:

• Materials Science
• Additive Manufacturing
• Microfluidics

Background:

• Current 3D printing inks are typically static, limiting the ability to vary composition and properties within printed objects.
• Existing methods for dynamic ink tuning are scarce, hindering the creation of complex functional materials.

Purpose of the Study:

• To develop a 3D printing approach for in-situ modulation of ink composition and properties.
• To demonstrate the ability to tune mechanical characteristics and impart functionality to printed constructs.

Main Methods:

• Utilizing a microfluidic device as a printhead to disperse droplets within a continuous phase (polydimethylsiloxane - PDMS).
• 3D printing the resulting emulsion into various structures.
• Incorporating aqueous droplets (poly(ethylene glycol) diacrylate - PEGDA) and ferrofluid droplets.

Main Results:

• Successfully tuned mechanical properties of 3D-printed PDMS constructs by altering droplet distribution, achieving an 85% reduction in elastic modulus using PEGDA droplets.
• Imparted magnetic responsiveness to PDMS by dispersing ferrofluid droplets.
• Designed and printed a rudimentary magnetically responsive soft robotic actuator.

Conclusions:

• The droplet-based strategy enables dynamic control over material properties during 3D printing.
• This microfluidic-assisted additive manufacturing approach opens new possibilities for creating advanced functional materials and devices.