부산대학교 도서관

Soft materials that can dynamically reconfigure its morphology upon interaction with environment or perceptions of information is currently thriving. Among these materials, magnetic hydrogels offer great opportunities for novel applications, particularly within biomedical field. However, the design of magnetic hydrogels is rather complicated since (i) it concurrently combines large deformation, magneto-active response and solvent diffusion, and (ii) the relationship remains unclear between the hydrogel performance and various magnetic field types, including uniform, nonuniform, and low-frequency alternating magnetic fields. Herein, a multiphysics model is developed to characterize the coupled processes of hydrogel magnetization, solvent diffusion and large deformation of the hydrogel, based on a general thermodynamically consistent framework. In particular, the magnetic boundary conditions are specified by solving the Laplace's equation for the magnetic scalar potential if a nonuniform magnetic field is imposed. Various case studies are conducted to investigate the influences of magnetic permeability, field distribution coefficients, and hydrogel-magnet distance on the hydrogel performance. The numerical results show that the morphology of the hydrogel can be rapidly tailored and the way it deforms changes significantly depending on the magnetic field type used. Additionally, the hydrogel elongates along the field direction under a uniform magnetic field, while it shrinks when a nonuniform magnetic field is applied. The present multiphysics model may provide theoretical guidance for optimal design and control of the magnetic hydrogel system.