Plant-inspired multi-stimuli and multi-temporal morphing composites

Abstract

Plants are inspiring models for adaptive, morphing systems. In addition to their shape complexity, they can respond to multiple stimuli and exhibit both fast and slow motion. We attempt to recreate these capabilities in synthetic structures, proposing a fabrication and design scheme for multi stimuli and multi temporal responsive plant-inspired composites. We leverage a hierarchical, spatially tailored microstructural and compositional scheme to enable both fast morphing through bistability and slow morphing through diffusion processes. The composites consisted of a hydrogel layer made of gelatine and an architected particle-reinforced epoxy bilayer. Using magnetic fields to achieve spatially distributed orientations of magnetically responsive platelets in each epoxy layer, complex bilayer architectural patterns in various geometries were realised. This feature enabled the study of plant-inspired complex designs, via finite element analysis and experiments. We present the design and fabrication strategy utilizing the material properties of the composites. The deformations and temporal responses of the resulting composites are analysed using digital image correlation. Finally, we model and experimentally demonstrate plant-inspired composite shells whose stable shapes closely mimic those of the Venus flytrap, while maintaining the multi stimuli and multi temporal responses of the materials. The key to achieve this is to tune the local in plane orientations of the reinforcing particles in the bilayer shapes, to induce distributed in plane mechanical properties and shrinkage. How these particles should be distributed is determined using finite element modelling. The work presented in this study can be applied to autonomous applications such as robotic systems.

Biomimetic Venus Flytrap Structures Using Smart Composites: A Review

“…A further strategy is considering multiple driving methods to mimic the biomechanics of the flytrap. Figure 7 shows a design scheme using multi-stimulus and multi-temporal responsive composites, enabling both fast morphing through structural bistability and slow morphing through diffusion processes using hydrogel [72]. The multi-responsive composites consist of a hydrogel layer and an architected particle-reinforced epoxy bilayer.…”

Palm petiole inspired nonlinear anti-vibration ring with deformable crescent-shaped cross-section

“…These investigations replicate the geometry and properties of biological structures, typically bones and muscles, to achieve vibration isolation. Nevertheless, there are also plants with inherently flexible structures that offer both robust support properties and pliable characteristics [31,32]. These plants undergone billions of years of natural selection, and the structures of their roots, stems, and leaves conforms to their mechanical properties, with the optimal structural form that adapts to the environment [33][34][35].…”

4D hydrogels: fabrication strategies, stimulation mechanisms, and biomedical applications

“…1 For instance, several plants such as mimosa, Venus flytrap, and pinecones undergo a shape change in response to environmental stimuli (e.g., humidity, light, and touch) to adapt to ever-changing complex environments. 2 Dynamic shapes can be observed due to the anisotropic tissue composition and random orientation of micro-and nanostructures within the cell. Deformations typically arise from the out-of-plane and in-plane gradient created due to differences in local swelling behavior, amplifying the internal stresses under external stimuli.…”