Shape-morphing greenhouse: design of a thermally responsive transparent 4D-printed structure

Purpose Conventional greenhouse structures, particularly the multi-component assemblies of glass panels with rigid metal frames, face multiple limitations. Major advancements in FDM and four-dimensional (4D) printing offer a disruptive platform for macroscale responsive structure design. This project explores a proof-of-concept of using transparent polylactic acid (PLA) to create a single-part, thermally responsive greenhouse structure through 4D printing. The goal is to demonstrate the concept of passively opening at elevated temperatures, eliminating the need for complex assemblies with motors, sensors, and external control systems. Design/methodology/approach This research combines material characterization, bio-inspired ideation, and testing as part of the design methodology. Three actuation concepts, the pinecone, fish gills, and zero Poisson ratio (ZPR) mechanisms were developed and 3D printed. Each design was evaluated for optical transparency, structural stability, and thermal actuation. Findings Testing showed potential in using shape memory polymers for shape-morphing greenhouses, even though in this proof-of-concept there are limitations. PLA's relatively high glass transition temperature (63.5 °C) eliminates usage for real greenhouses, and opening was often gravity-driven rather than internal stress-induced. The pinecone design showed the most visible actuation but suffered from reduced transparency. The ZPR concept demonstrated potential for large-area openings but failed structurally. Originality/value The results highlight the potential of transparent PLA for 4D-printed responsive structures, enabling bio-inspired designs and morphing greenhouses. Recommendations include improving material responsiveness, integrating sealing features, optimising greenhouse parameters and further developing actuation mechanisms with modeling. This study provides an initial step toward scalable, electronics-free greenhouse ventilation systems.