Construction of a photothermal Venus flytrap from conductive polymer bimorphs

A photothermally foldable soft bimorph was prepared via the dry transfer of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with tosylate onto a poly(dimethylsiloxane) film. The photothermal folding was optimized via reversible actuation by controlling the thickness of each layer and the temperature increase to afford large deflection and displacement up to 150° and >20 mm, respectively, upon exposure to near-infrared (NIR) light (808 nm). A two-dimensional array of the bimorph converted into complex three-dimensional architectures, such as a Venus flytrap, under light and reversibly unfolded in the dark. Taking advantage of the photothermal nature of PEDOT, a localized heat pocket was generated inside the folding structure. Thus, a Venus flytrap with a hot pocket reaching 100 °C was realized for the first time. The Venus flytrap could trap and move an object within a few seconds of NIR exposure. A bilayer material that behaves like a Venus flytrap when illuminated by infrared light has been created by researchers in South Korea. Biomimetic materials – substances that replicate the behavior of biological organisms and structures – offer a route to producing engineered devices with novel functionality. The biomimetic material made by Eunkyoung Kim and colleagues from Yonsei University consists of two soft polymers – a spin–coated layer of polydimethylsiloxane (PDMS) on a spin-coated film of poly (3, 4–ethylenedioxythiophene) (PEDOT) doped with tosylate. PEDOT has photothermal properties, meaning that incident light leads to localized heating. This heat then changes the volume of the PDMS, which makes the bilayer fold. The team used this effect to create complex three–dimensional architectures and hot trap including a Venus flytrap, which snapped close within a few seconds of being exposed to near–infrared radiation. A photothermally foldable soft bimorph was prepared by dry transfer of poly(3,4-ethylenedioxythiophene)s (PEDOT) onto poly(dimethylsiloxane) film. The reversible folding nature of the soft bimorph was programmable to convert the two-dimensional (2D) array of bimorph into complex three-dimensional (3D) architectures such as Venus flytrap under light. These 3D structures were returned reversibly to the original unfolded 2D structures under dark. The Venus flytrap could perform a task to snap and move an object within few second of near-infrared exposure. A localized heat pocket was generated inside the folding structure due to the large photothermal effect of PEDOT.