Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
Structural Engineering Department University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
Soft Matter. 2022 Nov 30;18(46):8771-8778. doi: 10.1039/d2sm01104b.
The stimuli-responsive self-folding structure is ubiquitous in nature, for instance, the mimosa folds its leaves in response to external touch or heat, and the Venus flytrap snaps shut to trap the insect inside. Thus, modeling self-folding structures has been of great interest to predict the final configuration and understand the folding mechanism. Here, we apply a simple yet effective method to predict the folding angle of the temperature-responsive nanocomposite hydrogel/elastomer bilayer structure manufactured by 3D printing, which facilitates the study of the effect of the inevitable variations in manufacturing and material properties on folding angles by comparing the simulation results with the experimentally measured folding angles. The defining feature of our method is to use thermal expansion to model the temperature-responsive nanocomposite hydrogel rather than the nonlinear field theory of diffusion model that was previously applied. The resulted difference between the simulation and experimentally measured folding angle (, error) is around 5%. We anticipate that our method could provide insight into the design, control, and prediction of 3D printing of stimuli-responsive shape morphing (, 4D printing) that have potential applications in soft actuators, robots, and biomedical devices.
刺激响应自折叠结构在自然界中无处不在，例如，含羞草会根据外部触摸或热量自行折叠叶片，维纳斯捕蝇草会关闭以捕捉内部的昆虫。因此，模拟自折叠结构对于预测最终构型和理解折叠机制非常重要。在这里，我们应用一种简单而有效的方法来预测通过 3D 打印制造的温度响应纳米复合水凝胶/弹性体双层结构的折叠角度，通过将模拟结果与实验测量的折叠角度进行比较，研究制造和材料特性不可避免的变化对折叠角度的影响。我们方法的特点是使用热膨胀来模拟温度响应纳米复合水凝胶，而不是以前应用的扩散模型的非线性场理论。模拟和实验测量的折叠角度之间的差异（误差）约为 5%。我们预计，我们的方法可以为刺激响应形状变形（4D 打印）的 3D 打印设计、控制和预测提供见解，这些在软执行器、机器人和生物医学设备中有潜在的应用。
