%0 Journal Article %1 tahouni2021programming %A Tahouni, Yasaman %A Krüger, Friederike %A Poppinga, Simon %A Wood, Dylan %A Pfaff, Matthias %A Rühe, Jürgen %A Speck, Thomas %A Menges, Achim %D 2021 %J Bioinspiration & Biomimetics %K AP1 P215 from:tiffanycheng matpro peer %R https://doi.org/10.1088/1748-3190/ac0c8e %T Programming sequential motion steps in 4D-printed hygromorphs by architected mesostructure and differential hygro-responsiveness %X Through their anisotropic cellular mesostructure and differential swelling and shrinkingproperties, hygroscopic plant structures move in response to changes in the environment withoutconsuming metabolic energy. When the movement is choreographed in sequential time steps,either in individual structures or with a coordinated interplay of various structural elements,complex functionalities such as dispersal and protection of seeds are achieved. Inspired by themulti-phase motion in plant structures, this paper presents a method to physically program thetimescale and the sequences of shape-change in 4D-printed hygromorphic structures. Using theFDM 3D-printing method, we have developed multi-layered, multi-material functional bilayersthat combine highly hygroscopic active layers (printed with hygroscopic bio-composite materials)with hydrophobic restrictive and blocking layers (printed with PLA and TPC materials). Thetimescale of motion is programmed through the design of the mesostructured layers and3D-printing process parameters, including thickness (number of printed active layers), porosity(filling ratio of the active layer), and water permeability (filling ratio of the blocking layer).Through a series of experiments, it is shown that the timescale of motion can be extended byincreasing the thickness of the active layer, decreasing the porosity of the active layer, or increasingthe filling ratio of the hydrophobic restrictive and blocking layers. Similarly, a lower thickness of theactive layer and lower filling ratio of all layers result in a faster motion. As a proof of concept, wedemonstrate several prototypes that exhibit sequential motion, including an aperture withoverlapping elements where each completes its movement sequentially to avoid collision, and aself-locking mechanism where defined areas of the structure are choreographed to achieve amulti-step self-shaping and locking function. The presented method extends the programmabilityand the functional capabilities of hygromorphic 4D-printing, allowing for novel applications acrossfields such as robotics, smart actuators, and adaptive architecture.

@article{tahouni2021programming, abstract = {Through their anisotropic cellular mesostructure and differential swelling and shrinkingproperties, hygroscopic plant structures move in response to changes in the environment withoutconsuming metabolic energy. When the movement is choreographed in sequential time steps,either in individual structures or with a coordinated interplay of various structural elements,complex functionalities such as dispersal and protection of seeds are achieved. Inspired by themulti-phase motion in plant structures, this paper presents a method to physically program thetimescale and the sequences of shape-change in 4D-printed hygromorphic structures. Using theFDM 3D-printing method, we have developed multi-layered, multi-material functional bilayersthat combine highly hygroscopic active layers (printed with hygroscopic bio-composite materials)with hydrophobic restrictive and blocking layers (printed with PLA and TPC materials). Thetimescale of motion is programmed through the design of the mesostructured layers and3D-printing process parameters, including thickness (number of printed active layers), porosity(filling ratio of the active layer), and water permeability (filling ratio of the blocking layer).Through a series of experiments, it is shown that the timescale of motion can be extended byincreasing the thickness of the active layer, decreasing the porosity of the active layer, or increasingthe filling ratio of the hydrophobic restrictive and blocking layers. Similarly, a lower thickness of theactive layer and lower filling ratio of all layers result in a faster motion. As a proof of concept, wedemonstrate several prototypes that exhibit sequential motion, including an aperture withoverlapping elements where each completes its movement sequentially to avoid collision, and aself-locking mechanism where defined areas of the structure are choreographed to achieve amulti-step self-shaping and locking function. The presented method extends the programmabilityand the functional capabilities of hygromorphic 4D-printing, allowing for novel applications acrossfields such as robotics, smart actuators, and adaptive architecture.}, added-at = {2021-07-06T00:11:06.000+0200}, author = {Tahouni, Yasaman and Krüger, Friederike and Poppinga, Simon and Wood, Dylan and Pfaff, Matthias and Rühe, Jürgen and Speck, Thomas and Menges, Achim}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/235ac06aaaf085b04950732afebb79142/icd}, doi = {https://doi.org/10.1088/1748-3190/ac0c8e}, interhash = {3ddb7a3a8a09fa9510dd581b76ee1da2}, intrahash = {35ac06aaaf085b04950732afebb79142}, journal = {Bioinspiration & Biomimetics}, keywords = {AP1 P215 from:tiffanycheng matpro peer}, timestamp = {2022-03-07T11:02:08.000+0100}, title = {Programming sequential motion steps in 4D-printed hygromorphs by architected mesostructure and differential hygro-responsiveness }, year = 2021 }