Columbia University

Technology Ventures

Soft robotic actuators based on highly expansive elastomers

Technology #cu16142

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Hod Lipson
Managed By
Richard Nguyen

This technology is an elastomeric actuator that captures the extreme volume expansion of the liquid-to-vapor transition to drive motion in soft robots.

Unmet Need: Motion actuators for soft robotics systems

Current robotic systems typically lack modular soft components to enable wide range of motion while retaining structural integrity. Consequently, this limits the range and precision of motion performance in soft robotics. As such, there is a need for motion actuators that are easily integrated, can perform dynamically with high precision, and can retain structural integrity throughout performance lifetimes.

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

This technology describes actuators for soft robotics that use simple chemistry and well-established phenomena to achieve high levels of reversible heat expansion. Specifically, this technology consists of a soft, plastic matrix that encapsulates electrical conductors and bubbles filled with high vapor pressure solvents. As current passes through the plastic matrix, the system is rapidly heated. The heat rapidly vaporizes solvent bubbles, which drives large volume expansion of the material. In the absence of an applied current, the actuator cools and contracts to the original state. Importantly, the technology retains its structural integrity after repeated expansion and contraction cycles and is assembled from inexpensive starting materials. In sum, this technology provides an inexpensive soft actuator that harnesses vapor-driven expansion for precise motion control in robotic machinery.

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


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


  • Captures heat expansion of the 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

Lead Inventor:

Hod Lipson, Ph.D.

Patent Information:

Patent Pending (WO/2017/096068)

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Tech Ventures Reference: