High Viscosity Liquid Processing for Tunable Graded Foams

THE CHALLENGE


The key challenge in developing liquid metal–elastomer composites for soft robotics and wearable electronics lies in achieving consistent, scalable manufacturing of these promising but technically complex materials. While direct ink writing offers a path to produce flexible, conductive structures, current methods struggle with controlling how the viscous, particle-filled inks behave during printing. Issues like filament spreading, uneven layering, and unpredictable pore structures lead to inconsistent product performance, especially in multi-layer designs. Without a reliable, repeatable process to fine-tune parameters such as nozzle height, flow rate, and droplet alignment, companies are forced to rely on trial-and-error, which drives up production time, costs, and variability. This lack of process standardization limits commercial scalability and makes it difficult to deliver reliable, high-performance products in areas that demand precision, such as medical wearables, adaptive sensors, and soft robotic components.

 

OUR SOLUTION


Our solution offers a breakthrough 3D printing method that enables consistent, scalable production of soft, conductive materials ideal for next-generation robotics, sensors, and wearable devices. By precisely controlling key parameters like nozzle height, ink flow, and print speed, we can fine-tune the shape and internal structure of each printed filament, avoiding common issues like surface roughness, layer defects, and uncontrolled porosity. A unique height compensation strategy maintains layer accuracy across complex builds, while real-time measurement tools ensure high-quality results. This process allows manufacturers to design materials with customized stiffness, density, and conductivity in a single print step, eliminating the need for costly trial-and-error or post-processing. The platform is compatible with standard extrusion hardware and supports high-viscosity composite inks, offering a commercially viable path to mass-produce multifunctional, soft materials with precision and repeatability.


Figure: DIW printing to control geometric structure and LM microstructure

Advantages:

  • Programmable porosity and functionally graded structures in a single print
  • Simultaneous control of microstructure and macroarchitecture
  • High-sensitivity capacitive sensing (gauge factor ~9.0)
  • Compatible with standard DIW printers and high-viscosity inks

Potential Application:

  • Soft capacitive strain and pressure sensors
  • Lightweight thermal interface materials
  • Functionally graded cushioning for soft robotics and prosthetics
  • EMI shielding foams

Patent Information: