形状记忆磁性润滑表面的制备及对超顺磁液滴的滑动操控

将磁性粒子与形状记忆聚合物复合,通过设计渐变式构型构筑了梯度形状磁性材料,并与润滑涂层相结合,制备了一种磁性润滑表面.在磁性梯度的作用下,超顺磁液滴在表面上能够自发定向运动.借助于材料形状记忆效应对表面区域形态进行可逆调控,进一步展示了超顺磁液滴自发定向运动过程中的启停开关式控制,实现了将液滴定向自发运输与启停控制相结合.考察了磁性粒子含量对材料形状记忆性能的影响,以及区域形态调控尺寸与液滴滑动性能间的相互关系.机理分析进一步阐明磁场梯度提供的定向驱动力促使液滴定向自发输运,表面区域形态控制的可逆调控则可以在液滴运动过程中增加/消除黏滞阻力,基于两种因素的协同作用,可以实现对超顺磁液滴运动的智能操控.

Magnetic Gradient Slippery Surfaces with Shape Memory Property for Smart Sliding Control of Superparamagnetic Droplet

A kind of magnetic material with gradient shape was prepared， which is composed of magnetic particles and shape memory polymers. After further coating the dimethyl silane lubricant， we obtained a magnetic gradient slippery surface. A superparamagnetic droplet can self-transport directionally on the surface under the effect of magnetic gradient. Meanwhile， reversible control of surface morphology can be achieved based on the shape memory effect， which is favorable for on/off control of droplet sliding. Based on the above two merits， the combination of directional self-transportation and on/off sliding control was successfully achieved. In addition， we also investigated the influence of magnetic particles content on the shape memory property of materials in detail and the relationship between the deformation size of surface morphology and superparamagnetic droplet sliding performance. The mechanism analysis further demonstrates that the self-transportation of superparamagnetic droplet is driven by the directional force provided by magnetic field gradient， the resistance can be increased/eliminated during droplet self-transportation by the reversible control of the morphology of the surface. The synergistic effect of these two factors endows the surface with excellent manipulation of superparamagnetic droplet.