Shape-memory polymers for microelectromechanical systems
Shape-memory polymers for microelectromechanical systems
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DOI：
10.1109/jmems.2004.828727
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发表时间：
2004-06-01
影响因子：
2.7
通讯作者：
Hulse, M
中科院分区：
文献类型：
--
作者：
Gall, K;Kreiner, P;Hulse, M
本文研究了形状记忆聚合物薄膜在微机电系统（MEMS）中的应用。形状记忆聚合物具有通过加热恢复大应变变形的能力，并且是小规模转换的候选物。形状记忆聚合物的主要优点是其低材料/制造成本以及其集成/操作的简单性。在本研究中，形状记忆聚合物旋涂到一个标准的硅晶片上，并通过热退火聚合。利用微压痕仪研究了聚合物薄膜中应变存储和恢复的热力学行为。尖锐的微压痕证明了在所有负载水平下的完全恢复，确立了微尺度致动的可行性。聚合物薄膜的微压痕响应取决于压痕过程中的温度和冷却周期。反过来，随后的恢复行为的一个压痕过程中的热历史依赖于。在较高温度下执行的压痕尺寸较大，但与在低温下执行的压痕相比具有较小的存储应变能。低温压痕中储存的较大的应变能导致较低的形状恢复温度。压痕温度和载荷的影响进行了系统的研究，提供了一个框架，在微系统中使用的形状记忆聚合物。形状记忆聚合物的应用是通过一个积极的微流控水库的发展。通过在微流体通道的端部处的压痕来创建储集器，并且通过局部加热来激活储集器。填充的储液器的塌陷导致流体沿微流体通道向下运动。
This paper investigates the use of shape-memory polymer thin films in microelectromechanical systems (MEMS). shape-memory polymers possess the capacity to recover large-strain deformations by the application of heat and are candidates for small-scale transduction. The key advantages of shape-memory polymers are their low material/fabrication cost coupled with their simplicity of integration/operation. In the present study, shape-memory polymers are spin coated onto a standard Si wafer and polymerized by thermal annealing. The thermomechanics of strain storage and recovery in the polymer films are studied using instrumented microindentation. The sharp microindents demonstrate full recovery at all load levels, establishing the feasibility of microscale actuation. The microindentation response of the polymer film is shown to depend on temperature and the cooling cycle during indentation. In turn, the subsequent recovery behavior of an indent depends on the thermal history during indentation. Indents performed at higher temperatures are larger in size, but have smaller stored strain energy compared to indents performed at low temperature. The larger stored strain energy in low temperature indents results in lower shape recovery temperatures. The effects of indentation temperature and load are systematically investigated to provide a framework for the use of shape-memory polymers in microsystems. Application of shape-memory polymers is demonstrated through the development of an active microfluidic reservoir. The reservoir was created by indentation at the end of a microfluidic channel and was activated by local heating. The collapse of the filled reservoir caused the motion of fluid down the microfluidic channel.