A novel approach on phase change actuators based on the stomata principle

• Presentation of a new concept of phase change actuators based on a biological principle. • Development of a manufacturing route and challenges of the joining process. • Numerical sensitivity analysis to investigate factors influencing actuator performance. • Comparison of the developed actuators with the biological models. Nature provides remarkable technical solutions and design principles that continue to inspire engineering innovation. One example is the independent opening and closing of stomata, specialised leaf cells that regulate a plant’s fluid balance. Transferring this principle into engineering offers new opportunities for efficient actuator design. Building on existing knowledge of paraffin-based phase change actuators (PCAs), which generate significant forces under thermal activation, a new concept for a curved PCA was developed. Numerical simulations were conducted to characterise actuator behaviour and identify key optimisation parameters. Based on these findings, a complete production chain was developed and implemented, including numerical design, manufacturing, and reliable sealing to withstand operational stresses. In an experimental test setup, the ’stoma actuators’ demonstrated significant movement, effectively validating the bionic concept. The results highlight the potential of the developed curved PCA, demonstrating how biologically inspired mechanisms can be translated into practical, functional actuator systems.