AI 中文总结
本研究通过分子动力学对比研究了相同饱和磁化强度下，填充硬磁与软磁粒子的磁活性弹性体的表面粗糙度与填料重构差异，明确了二者不同的演化路径，并指出需开发考虑羰基铁微粒子多畴特性的软磁模型。
AI 中文摘要
磁活性弹性体（MAEs）是嵌入软聚合物基质中的磁性纳米/微粒子复合材料，有望应用于软体机器人，因为其形状和力学性能可通过外加磁场控制。大多数MAE填充的是软磁（MS）微粒子，如羰基铁粉（CIP）。本研究采用分子动力学方法，对比研究了具有相同饱和磁化强度的、填充MS和硬磁（MH）填料粒子的薄MAE层的差异。研究发现，MH和MS弹性体均会收敛到相同的高场状态——由场对齐链形成的迷宫状束结构，但二者通过不同的路径实现：MH MAE会断裂其零场下平行于MAE层平面（面内）的链，并将其旋转至与外磁场对齐；而MS MAE则从相邻粒子逐步构建场对齐链。研究表明，MS模型在接近饱和的磁场下可复现基于CIP的MAE的磁化曲线和表面粗糙度，同时在较低场强下也能保持观测到的定性特征。模拟与低场实验结果的不匹配表明，需要开发一种考虑羰基铁微粒子多畴特性的MS模型。
英文摘要
Magneto-active elastomers (MAEs) -- composites of magnetic nano-/micro-particles embedded in a soft polymer matrix -- are promising for soft robotics, as their shape and mechanical properties can be controlled by an applied magnetic field. Most MAEs are filled with magnetically soft (MS) micro-particles, such as carbonyl iron powder (CIP). We employ molecular dynamics to study the differences between thin MAE layers with MS and magnetically hard (MH) filler particles having the same saturation magnetization. We find that both MH and MS elastomers converge to the same high-field state -- a labyrinth of bundled, field-aligned chains -- but do so through distinct pathways: MH MAEs break their zero-field chains, which lie parallel to the MAE layer plane (in-plane), and rotate them into alignment with an external magnetic field, whereas MS MAEs gradually build up field-aligned chains from neighboring particles. We show that the MS model reproduces the magnetization curves and surface roughness of CIP-based MAEs for magnetic fields close to saturation, while maintaining the observed qualitative features at lower field strengths. The mismatch between simulation and experimental results at low fields suggests the need for a MS model that accounts for the multi-domain nature of carbonyl iron microparticles.
