Temperature-memory polymer actuators
Temperature-memory polymer actuators
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DOI：
10.1073/pnas.1301895110
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发表时间：
2013-07-30
影响因子：
11.1
通讯作者：
Lendlein, Andreas
中科院分区：
文献类型：
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作者：
Behl, Marc;Kratz, Karl;Lendlein, Andreas
读出聚合物的温度记忆，即它们记住最近变形的温度的能力，到目前为止不可避免地与消除这种记忆效应有关。本文提出了一种基于具有宽熔融温度范围(Delta T-m)的交联型共聚网络的温度记忆聚合物致动器(TMPA)，这种致动器具有长期的温度记忆能力，可实现250多个几乎恒定性能的循环热控致动器。TMPAs的特征致动温度T(Act)S可以通过纯物理过程进行调整，通过改变参数T-Sep来引导定向结晶在高达40℃的温度范围内进行近乎线性的关联。温度T-Sep将Delta T-m分成较高的T-m范围(T&gT；T-Sep)和较低的T-m范围(T<；T-Sep)，形成了可重塑的致动几何形状，确定了骨架，而较低的T-m范围(T<；T-Sep)通过结晶诱导的伸长和熔融诱导的收缩实现了温度控制的双向致动。TMPAs的宏观双向形状变化可能与原位X射线研究结果所导致的结晶区纳米结构的变化相关联。TMPA的潜在应用包括具有可调节转速的热机和带有自我调节防晒器的主动建筑外立面。
Reading out the temperature-memory of polymers, which is their ability to remember the temperature where they were deformed recently, is thus far unavoidably linked to erasing this memory effect. Here temperature-memory polymer actuators (TMPAs) based on cross-linked copolymer networks exhibiting a broad melting temperature range (Delta T-m) are presented, which are capable of a long-term temperature-memory enabling more than 250 cyclic thermally controlled actuations with almost constant performance. The characteristic actuation temperatures T(act)s of TMPAs can be adjusted by a purely physical process, guiding a directed crystallization in a temperature range of up to 40 degrees C by variation of the parameter T-sep in a nearly linear correlation. The temperature T-sep divides Delta T-m into an upper T-m range (T > T-sep) forming a reshapeable actuation geometry that determines the skeleton and a lower T-m range (T < T-sep) that enables the temperature-controlled bidirectional actuation by crystallization-induced elongation and melting-induced contraction. The macroscopic bidirectional shape changes in TMPAs could be correlated with changes in the nanostructure of the crystallizable domains as a result of in situ X-ray investigations. Potential applications of TMPAs include heat engines with adjustable rotation rate and active building facades with self-regulating sun protectors.