Biodegradable Humidity Actuators for Sustainable Soft Robotics using Deliquescent Hydrogels

Alexander G Keller, Qiukai Qi*, Yogeenth Kumaresan, Andrew T Conn, Jonathan M Rossiter

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)


Intelligent materials offer new avenues when de-
signing sustainable robotics as they allow for the creation
of dynamic constructs which react autonomously to changes
in the environment, such as humidity. Here we present a
novel humidity actuator which exploits the unique property
of deliquescent salts to allow for the spontaneous rehydration
of hydrogels in ambient environments. By soaking a 2% w/v
alginate, 3% w/v Agar composite in 1M calcium chloride,
an intelligent humidity-driven actuator was developed. The
hydrogel was able to gain 73.8±7.1% of its weight from a
dehydrated state in just 6 hours through water absorption
from ambient air. Using this novel formulation, linear and
bilayer bending actuators were constructed. In addition to
this, a biodegradable deliquescence-actuated artificial flower
was demonstrated, highlighting this material’s potential to act
as an intelligent humidity actuator for the construction of
environmentally-reactive biomimetic sustainable robotics.
Original languageEnglish
Title of host publication2023 IEEE 6th International Conference on Soft Robotics (RoboSoft)
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Publication statusAccepted/In press - 3 Apr 2023
Event6th IEEE-RAS International Conference on Soft Robotics (RoboSoft) - Marina Bay Sands, Singapore, Singapore
Duration: 3 Apr 20237 Apr 2023


Conference6th IEEE-RAS International Conference on Soft Robotics (RoboSoft)
Abbreviated titleRoboSoft 2023
Internet address


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