An autonomous actuator driven by fluctuations in ambient humidity.

@article{Arazoe2016AnAA,
  title={An autonomous actuator driven by fluctuations in ambient humidity.},
  author={Hiroki Arazoe and Daigo Miyajima and Kouki Akaike and Fumito Araoka and Emiko Sato and Takaaki Hikima and Masuki Kawamoto and Takuzo Aida},
  journal={Nature materials},
  year={2016},
  volume={15 10},
  pages={
          1084-9
        }
}
Devices that respond to negligibly small fluctuations in environmental conditions will be of great value for the realization of more sustainable, low-power-consumption actuators and electronic systems. Herein we report an unprecedented film actuator that seemingly operates autonomously, because it responds to the adsorption and desorption of a minute amount of water (several hundred nanograms per 10 mm(2)) possibly induced by fluctuations in the ambient humidity. The actuation is extremely… 
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