Highly sensitive humidity-driven actuators based on metal-organic frameworks incorporating thermoplastic polyurethane with gradient polymer distribution.

Ambient humidity plays an important role in the fields of industrial and agricultural production, food and drug storage, climate monitoring, and maintenance of precision instruments. To sense and control humidity, humidity-responsive actuators that mimick humidity responsive behavior existing in nature, have attracted intense attention. The most common and important class of humidity actuators is active bilayer structures.