Humidity Responsive Asymmetric Free-Standing Multilayered Film

L. Shen (1) , J. Fu (2) , K. Fu (2) , C. Picart (3) , J. Ji (2)

1 IMBM
2 MOE Key Laboratory of Macromolecular Synthesis and Functionalization
3 IMBM

A humido-responsive free-standing film has been created using layer-by-layer assembly technique. Polyethylenimine (PEI) at high pH was assembled with poly(acrylic acid) (PAA) at low pH on a Teflon substrate to yield a micro-nanostructured surface that can be made superhydrophobic after being coated with a low surface energy compound. The resulting asymmetric free-standing film with one surface being superhydrophobic while the other is hydrophilic after detachment from the substrate can undergo reversible bending/unbending shape transitions when the environmental humidity is changed. The bending/unbending movement of the free-standing film can be ascribed to the different responses of these two surfaces to humidity.

L. Shen, J. Fu, K. Fu, C. Picart, J. Ji. Humidity Responsive Asymmetric Free-Standing Multilayered Film. Langmuir, 2010, pp.26 (22) 16634-16637. ⟨10.1021/la102928g⟩. ⟨hal-00670223⟩