Enhanced Variable Stiffness and Variable Stretchability Enabled by Phase-Changing Particulate Additives
Enhanced Variable Stiffness and Variable Stretchability Enabled by Phase-Changing Particulate Additives
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DOI：
10.1002/adfm.201903368
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发表时间：
2019-10-03
影响因子：
19
通讯作者：
Kramer-Bottiglio, Rebecca
中科院分区：
文献类型：
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作者：
Buckner, Trevor L.;Yuen, Michelle C.;Kramer-Bottiglio, Rebecca
介绍了一种新型相变颗粒，它可以放大复合材料在热刺激下的模量变化。这种颗粒添加剂由低熔点合金（Field's metal； FM）组成，通过简单的制造方法形成微颗粒，使其能够通过简单的复合制造工艺融入聚合物基质中。在两种主体材料：热敏环氧树脂和硅酮弹性体中证明了FM颗粒的固液相变化的影响。在环氧树脂基体中，这种热响应表现为加热时弯曲模量的放大变化，这对于改变刚度的移动和保持应用是非常理想的。在有机硅基体中，可拉伸性可以根据FM颗粒的相位进行切换。这种现象允许硅酮拉伸并保持应变配置，并通过FM内含物的重塑产生机械可编程的各向异性。FM颗粒在需要按需可调模数的地方提供了许多机会，并且与软机器人技术特别相关。由于调频的熔化温度接近室温，触发相变所需的功耗较低。证明了含FM颗粒复合材料作为柔性机器人的变刚度和变拉伸元件的实用性。
A novel phase-changing particulate that amplifies a composite's modulus change in response to thermal stimulus is introduced. This particulate additive consists of a low melting point alloy (Field's metal; FM) formed into microparticles using a facile fabrication method, which enables its incorporation into polymer matrices using simple composite manufacturing processes. The effect of the solid-liquid phase change of the FM particles is demonstrated in two host materials: a thermally responsive epoxy and a silicone elastomer. In the epoxy matrix, this thermal response manifests as an amplified change in flexural modulus when heated, which is highly desirable for stiffness-changing move-and-hold applications. In the silicone matrix, the stretchability can be switched depending on the phase of the FM particles. This phenomenon allows the silicone to stretch and hold a strained configuration, and gives rise to mechanically programmable anisotropy through reshaping of the FM inclusions. FM particles present many opportunities where on-demand tunable modulus is required, and is particularly relevant to soft robotics. Because the melting temperature of FM is near room temperature, triggering the phase change requires low power consumption. The utility of FM particle-containing composites as variable stiffness and variable stretchability elements for soft robotic applications is demonstrated.