Embodying intelligence into materials requires engineering systems that can autonomously sense, adapt, and respond to environmental stimuli, similar to the dynamic behaviours of living organisms. Realizing this in practical devices remains a scientific grand challenge with direct implications for soft robotics, bioengineering, and medicine. Researchers have previously developed stimuli-responsive hydrogels and biohybrid constructs that interface with living systems; however, these devices often remain tethered, constrained, or limited to specific environments, such as patterned surfaces. In this talk, I present my research on untethered, thermoresponsive hydrogel robots that crawl autonomously across unpatterned surfaces. I designed multisegmented bilayer gelbots composed of active poly(N-isopropylacrylamide) (pNIPAM) and passive polyacrylamide (pAAM), connected by suspended linkers. We validated the experiments using finite element simulations and proved these robots consistently achieve unidirectional motion through spontaneous asymmetries in contact forces generated during an actuation cycle. I further validated the model by demonstrating that I could tune gelbot displacement through design parameters such as linker stiffness, morphology, and number of bilayer segments. This framework charts a path toward untethered, intelligent soft robots with applications in targeted drug delivery, minimally invasive surgery, and programmable bio-actuation.

Learning Objectives:

1. Describe how thermoresponsive hydrogels enable autonomous movement in untethered soft robots.

2. Explain how design parameters such as linker stiffness, morphology, and bilayer segmentation influence gelbot displacement.

3. Assess potential biomedical and engineering applications of untethered hydrogel-based soft robots.