Nutz Fabian A, Retsch Markus
Department of Chemistry, University of Bayreuth, Universitaetsstraβe 30, 95447 Bayreuth, Germany.
Sci Adv. 2017 Nov 17;3(11):eaao5238. doi: 10.1126/sciadv.aao5238. eCollection 2017 Nov.
Managing heat is a major challenge to meet future demands for a sustainable use of our energy resources. This requires materials, which can be custom-designed to exhibit specific temperature-dependent thermal transport properties to become integrated into thermal switches, transistors, or diodes. Common crystalline and amorphous materials are not suitable, owing to their gradual changes of the temperature-dependent thermal conductivity. We show how a second-order phase transition fully controls the temperature-dependent thermal transport properties of polymer materials. We demonstrate four major concepts based on a colloidal superstructure: (i) control of transition temperature, (ii) width of phase transition regime, (iii) multistep transitions, and (iv) step height of the transition. Most importantly, this unique control over thermal conductivity is only governed by the interparticle constriction, the particle composition, and its mesostructure. Our concept is therefore also applicable to a wide variety of other particulate materials.
应对热量问题是满足未来可持续利用能源资源需求的一项重大挑战。这就需要能够根据特定需求进行定制设计的材料，使其展现出特定的随温度变化的热传输特性，从而集成到热开关、晶体管或二极管中。常见的晶体材料和非晶材料并不适用，因为它们的热导率随温度呈逐渐变化。我们展示了二阶相变如何完全控制聚合物材料随温度变化的热传输特性。我们基于胶体超结构论证了四个主要概念：（i）转变温度的控制，（ii）相变区域的宽度，（iii）多步转变，以及（iv）转变的台阶高度。最重要的是，这种对热导率的独特控制仅由颗粒间的收缩、颗粒组成及其介观结构决定。因此，我们的概念也适用于多种其他颗粒材料。
