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Kulkarni et al. Soft Sci. 2025, 5, 12 https://dx.doi.org/10.20517/ss.2023.51 Page 3 of 35

Figure 1. This review focuses on the challenges and opportunities of engineering soft actuators and soft sensors in extreme
environments including inside the human body [20] , marine exploration [21] , space exploration [22] , and search, rescue, and confined
spaces [23] . [Images are licensed under CC BY 4.0. http://creativecommons.org/licenses/by/4.0/].

motions or the ability to lift heavy loads are required. Soft robots also have limitations regarding actuation
speed and accuracy depending on the material and actuator type. Despite these limitations, soft robotics
research is rapidly evolving, and new structures continually improve upon these shortcomings. Table 1
summarizes these benefits by comparing the advantages of soft and rigid materials for applications
requiring flexibility, resistance to brittle failure, thermal insulation, biocompatibility, and self-healing
capabilities in extreme environments.

Pneumatic and hydraulic-driven soft actuators composed of elastomeric materials can withstand
compressive loads and enable impact absorption due to their deformable structure . Durability and
[25]
puncture resistance can be further enhanced in elastomeric composites with fiber or fabric
reinforcements . Fabric-reinforced composite materials allow for tunable mechanical properties including
[43]
improved tear and puncture resistance in pneumatic networks . Flexible and deformable material
[43]
compositions enable bending, torsion, expansion, and contraction motions in soft robots . Soft robotic
[44]
systems are commonly fabricated from materials with an elastic modulus, E, ranging from 10 to 10 Pa,
9
4
9
providing flexibility compared to rigid robots, which comprise materials with elastic moduli within 10 to
10 Pa .
[28]
12
Soft robots also offer unique qualities including extrinsic or intrinsic self-healing properties, making them
beneficial for operations in unpredictable environments. Extrinsic self-healing materials consist of healing