Preparation Technology Of Fe₃O₄/Gelatin Sodium Alginate Magnetic Multi Joint Soft Mechanical Finger

Fe₃O₄ nanoparticles are a kind of material with excellent superparamagnetism.Adding them to gelatin sodium alginate hydrogel can make the hydrogel have the characteristics of rapid response in magnetic field.In this paper,hydrophilic Fe₃O₄ particles of about 20 nm were prepared,and they were added to gelatin sodium alginate to prepare magnetic hydrogel.Their morphology and performance were analyzed,and the effect of Fe₃O₄ addition amount on the performance of magnetic hydrogel under the action of magnetic field was explored,Finally,using the method of bioprinting,a multi joint magnetic soft mechanical finger was prepared,and some basic research was done in the field of soft mechanical fingers.Firstly,in this experiment,Fe₃O₄ magnetic particles were prepared by coprecipitation method,and a layer of surfactant was added to their surface to make them hydrophilic.Then,the synthesized Fe₃O₄particles were characterized by X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR）,transmission electron microscopy（TEM）,and magnetic hysteresis loop analyzer.The results show that hydrophilic Fe₃O₄ magnetic particles with a particle diameter of about 20 nm have been successfully synthesized and can be uniformly dispersed in aqueous solution,indicating their good hydrophilicity.The magnetic test results show that the spinel Fe₃O₄ particles have good ferromagnetism,which also proves that they can have good magnetic responsiveness in the magnetic field.The prerequisite for preparing good magnetic hydrogels is that the magnetic particles have hydrophilicity and magnetic responsiveness.Secondly,Fe₃O₄ particles were mixed with gelatin sodium alginate hydrogel to form a magnetic hydrogel,and the structure and performance of the magnetic hydrogel were analyzed by Fourier transform infrared spectroscopy（FTIR）,film tensile testing machine,thermogravimetric analysis（TGA）,dynamic thermal mechanical analysis（DMA）,etc.The results show that the prepared magnetic hydrogel has good magnetic responsiveness,and the addition of Fe₃O₄ particles also improves the tensile strength,thermal stability and storage modulus of the magnetic hydrogel,because the uniform distribution of Fe₃O₄particles in the three-dimensional network structure of the hydrogel leads to the improvement of the mechanical properties of the hydrogel,but because the distribution of Fe₃O₄ particles occupies the space of the three-dimensional network in the magnetic hydrogel,the water content in the hydrogel is reduced,As a result,the swelling degree of the hydrogel decreased to a certain extent.Finally,the influence of Fe₃O₄ particles on the magnetic properties of the hydrogel under the action of magnetic field was analyzed and studied,and the formula of the magnetic hydrogel was completed.Finally,the printing process parameters were studied for the performance of the product,and a multi joint magnetic soft mechanical finger was designed through the above formula invention,and successfully prepared using 3D printing technology.As a basic research for developing a soft robot such as a robot hand,this mechanical finger has low cost and simple control,The mass fraction of magnetic nanoparticles in each joint can be adjusted accordingly based on the grasping needs of the object and the spatial posture required by the mechanical finger,resulting in better reconfigurability.