4D printing of magnetism-responsive shape-morphing polymers

• Main Author: Liew, Marcus Guan Wen
• Other Authors: Zhou Kun
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Additive manufacturing; 4D printing
• Online Access: https://hdl.handle.net/10356/177840
• Institution: Nanyang Technological University

4D printed magnetic actuators are widely sought after due to its high-tech capabilities and flexibility as a composite material, with the ability to transform and eliminate excess manufacturing processes from the current norm, and potentially serve as a better candidate for a product. Challenges that arise from printing such product include its material limitations in terms of mechanical properties and printability, complexity in design, precise in dimensions and the future scalability in terms of additive manufacturing. The research gap for this report includes the processing of materials, study on the performance and reliability of such materials, control mechanisms and potential future applications. Under methodology, a variety of methods and procedures are used, such as, ink preparation of the composite material, setting of printing parameters of the machine, magnetizing the product with an impulse magnetizer to study the effects of magnetic fields to the material, and the material’s characteristics by undergoing different types of characterization tests. Results and discussions will closely monitor the characterization of the ink and both mechanical and thermal properties will be recorded. Microscopy test will conclude the ink composite’s size of magnetic NdFeB microparticles and the presence of such on the surface, where an evenly spread out is the ideal case. In conclusion, key properties such as phase transition temperatures and shear-thinning behaviour were identified using DSC and rheological analysis. SEM imaging of NdFeB microparticles revealed size variations which affects mesogen alignment and thermal actuation. Despite agglomeration impacts mechanical properties, composite product of the LCE/NdFeB ink composite exhibited promising stimuli-responsive behaviour, particularly in thermal actuation. Research provides valuable insights into formulating viscoelastic nematic inks and developing advanced composites. For recommendations, to improve the even distribution of NdFeB particles, further optimization of DIW printing parameters is necessary, including ink viscosity, extrusion pressure, printing speed, and nozzle temperature. Future work should focus on magnetizing the printed LCE composite films to align the magnetic domains of NdFeB, enabling controllable shape-changing behaviours and part mating.