Columbia University

Technology Ventures

Soft robotic actuators based on highly expansive elastomers

Technology #cu16142

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Hod Lipson
Managed By
Richard Nguyen

The development of soft robotics is critical to advance automation, especially when robots interface with humans. Currently, there is a need to develop modular soft components, and especially actuators for motion, that can be easily integrated into robotic systems. This technology is an elastomeric actuator that captures the extreme volume expansion of the liquid-to-vapor transition to drive motion in soft robots. Electrical current is used to heat the system and drive volume expansion, and fast heating and cooling endows the user with precise control over volume changes and actuation. The technology retains its structural integrity while accomplishing high levels of repeated expansion and contraction to its original volume. Moreover, the technology is comprised of inexpensive materials and is put together in straightforward ways to optimize cost efficiency. As such, the technology is able to provide high impact actuators for soft robotics without high manufacturing cost or complex assembly.

Vapor-driven expansion in soft actuators easily controlled by electrical current

This technology includes designs of actuators for soft robotics that use simple chemistry and well-established phenomena to achieve high levels of reversible heat expansion. Specifically, it is a soft, plastic matrix that encapsulates electrical-conductors and bubbles filled with high vapor pressure solvents. The incorporation of electrically conducting material enables current to pass through the plastic matrix and heat the system. The heat effectively vaporizes solvent bubbles, which drives large volume expansion of the material. This actuator cools and contracts readily when current is not applied, endowing the user with precise control over soft robotic machinery with this technology as the foundation.

A prototype of this technology has been tested and shown to exhibit current tunable expansion and contraction for soft robotic actuation.

Lead Inventor:

Hod Lispson, Ph.D.


  • Actuators for soft robotics
  • Heat sensors
  • Biomedical devices, prosthetics
  • Artificial muscles


  • Captures heat expansion of liquid-to-vapor phase transition
  • Inexpensive materials assembled in a straightforward manner
  • Electrical control over expansion and contraction
  • Retains mechanical integrity over many expand/contract cycles

Patent Information:

Patent Pending

Tech Ventures Reference: IR CU16142

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