Material programming for 4D-printing : architected mesostructures for bioinspired self-shaping

Abstract

Material, structure, and function are tightly intertwined in nature. The movement of plants, for instance, is often encoded through the structuring of tissue materials, allowing plants to change shape over a range of spatial-temporal scales when powered by environmental stimuli. In contrast, the human practice of design and production relies on discrete parts for sensing, actuation, or control. Individual components are sourced worldwide to be assembled into complex systems that demand significant energy for operation. This divergence from nature's strategy is changing the climate and contributing to environmental degradation. This dissertation presents a bioinspired approach to design and fabrication as an alternative to conventional methods of making. The interplay of cellulosic materials, mesostructures, and adaptive response is managed through the developed computational fabrication framework, resulting in hygromorphic 4D-printed systems powered by the free-flowing moisture inputs of the environment. The framework is also generalizable to diverse materials and processes, as showcased through the upscaling of the methods to an industrial robot platform to construct self-shaping hybrid materials systems. Finally, the framework's applicability is proven through the transfer of design principles from biology to self-adjusting wearables for the body and weather-responsive facades for buildings. The presented material programming approach has wide-ranging potential across scales and disciplines, demonstrating that by harnessing biobased materials, material-efficient structures, and environmental input for energy, bioinspired 4D-printing can overcome the competing resources between nature and technology.