Fabricating soft functional materials via additive manufacturing is an emerging field with a wide variety of applications due to their ability to respond to specifically engineered stimuli (e.g., mechanical, electrical, magnetic, chemical). This article describes an approach to engineering magnetically sensitive structures using three-dimensional printing of acrylonitrile butadiene styrene scaffolds. These scaffolds are encapsulated in polydimethylsiloxane (PDMS) and removed using organic solvents. The open channels that remain after removal are filled in with a ferrofluid to render the structure magnetically sensitive. A three-point flexural test shows that introducing a channel in this way only reduces the flexural modulus of the PDMS by a factor ∼8%. We perform magnetic deflection experiments on samples with three different channel diameters. Our results show a linear dependence between applied magnetic field strength and deflection. We also find that there is a minimum magnetic field strength that needs to be applied to achieve deflection. These results suggest that there is a minimum yield stress, beyond which deflection will occur. We perform experiments on a more complex channel geometry to find that there are multiple modes of deflection. A rational approach to channel design may enable us to tune the mechanical response and direct these actuators to undergo complex motion.

中文翻译：

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基于 3D 打印支架移除的软铁磁流体致动器

通过增材制造制造软功能材料是一个具有广泛应用的新兴领域，因为它们能够响应专门设计的刺激（例如，机械、电、磁、化学）。本文介绍了一种使用丙烯腈丁二烯苯乙烯支架的三维打印来设计磁敏结构的方法。这些支架封装在聚二甲基硅氧烷 (PDMS) 中，并使用有机溶剂去除。去除后留下的开放通道用铁磁流体填充，使结构具有磁性。三点弯曲测试表明，以这种方式引入通道只会将 PDMS 的弯曲模量降低约 8%。我们对具有三种不同通道直径的样品进行磁偏转实验。我们的结果表明施加的磁场强度和偏转之间存在线性相关性。我们还发现需要施加最小磁场强度才能实现偏转。这些结果表明存在最小屈服应力，超过该应力就会发生变形。我们对更复杂的通道几何形状进行实验，发现存在多种偏转模式。合理的通道设计方法可能使我们能够调整机械响应并引导这些执行器进行复杂的运动。我们对更复杂的通道几何形状进行实验，发现存在多种偏转模式。合理的通道设计方法可能使我们能够调整机械响应并引导这些执行器进行复杂的运动。我们对更复杂的通道几何形状进行实验，发现存在多种偏转模式。合理的通道设计方法可能使我们能够调整机械响应并引导这些执行器进行复杂的运动。