The ability to program the behavior of magneto-reactive polymers requires the fine control of their magnetic microstructure during each step of the printing process. Here, a systematic study of magnetically driven self-assembly of Fe₃O₄ nanoparticles into chain-like structures is presented and used in a 3D printable formulation. The kinetics of chains formation, as well as their rotation, are studied by varying several experimental parameters: i.e. the viscosity of the formulation, the content of nanoparticles, the intensity of the applied magnetic field, and its application time. Experimental results are coupled to numerical simulations based on the dipolar approximation model, and the collected data are used to produce a dataset to precisely program the microstructure during the printing step. Thus, a desired microstructure in a 3D printed piece can be obtained by controlling the orientation and the length of the magnetic chains in each printed layer. This is achieved by modifying a commercial Digital Light Processing (DLP) 3D printer to apply magnetic fields of tunable intensity and direction. Finally, as a proof of concept, a pyramid-like structure was 3D printed, where each layer contains a specific and spatially oriented microstructure.

对磁反应聚合物的行为进行编程的能力需要在印刷过程的每个步骤中对其磁性微观结构进行精细控制。在此，系统研究 Fe ₃ O ₄的磁驱动自组装将纳米颗粒转化为链状结构并用于 3D 可打印配方。通过改变几个实验参数来研究链形成的动力学以及它们的旋转：即制剂的粘度、纳米颗粒的含量、施加的磁场强度及其施加时间。实验结果与基于偶极近似模型的数值模拟相结合，收集的数据用于生成数据集，以便在打印步骤中对微观结构进行精确编程。因此，可以通过控制每个打印层中磁链的方向和长度来获得 3D 打印件中所需的微观结构。这是通过修改商用数字光处理 (DLP) 3D 打印机来应用强度和方向可调的磁场来实现的。最后，作为概念证明，3D 打印了金字塔状结构，其中每一层都包含特定的空间定向微结构。