High-contrast and reversible polymer thermal regulator by structural phase transition
High-contrast and reversible polymer thermal regulator by structural phase transition
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DOI：
10.1126/sciadv.aax3777
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发表时间：
2019-12-01
期刊：
影响因子：
13.6
通讯作者：
Shen, Sheng
中科院分区：
文献类型：
--
作者：
Shrestha, Ramesh;Luan, Yuxuan;Shen, Sheng
与电子学中的可切换、非线性和有源元件的进步相比，用于主动控制热流的固态热元件已经极其罕见。我们展示了一种高对比度和可逆的聚合物热调节剂的结晶聚乙烯纳米纤维的结构相变的基础上。这种结构相变代表了从高度有序的全反式构象到具有旋转无序的组合反式和笨拙构象的形态的急剧变化，导致声子传输沿着分子链的突然变化。对于这里测量的五个样品，我们观察到类似于8x的平均热开关比和类似于10 x的最大开关比，这发生在10 K的狭窄温度范围内的结构相变。据我们所知，类似于10倍的切换比超过了任何报道的材料固-固和固-液相变的实验值。在加热/冷却循环时没有观察到热滞后。
In comparison with the advancement of switchable, nonlinear, and active components in electronics, solid-state thermal components for actively controlling heat flow have been extremely rare. We demonstrate a high-contrast and reversible polymer thermal regulator based on the structural phase transition in crystalline polyethylene nanofibers. This structural phase transition represents a dramatic change in morphology from a highly ordered all-trans conformation to a combined trans and gauche conformation with rotational disorder, leading to an abrupt change in phonon transport along the molecular chains. For five nanofiber samples measured here, we observe an average thermal switching ratio of similar to 8x and maximum switching ratio of similar to 10x, which occurs in a narrow temperature range of 10 K across the structural phase transition. To the best of our knowledge, the similar to 10x switching ratio exceeds any reported experimental values for solid-solid and solid-liquid phase transitions of materials. There is no thermal hysteresis observed upon heating/cooling cycles.