沿着自组织氨基酸晶体加快界面约束聚合物链中的声子转移,ACS Applied Materials & Interfaces

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沿着自组织氨基酸晶体加快界面约束聚合物链中的声子转移
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2017-03-24 00:00:00 , DOI: 10.1021/acsami.7b02257
Liwen Mu ₁ , Yifan Li ₁ , Nitin Mehra ₁ , Tuo Ji ₁ , Jiahua Zhu ₁

Affiliation

在这项工作中，通过自组织结晶过程制备了聚乙烯醇（PVA）/氨基酸（AA）复合材料。基于五种不同的氨基酸（半胱氨酸，天冬氨酸，谷氨酸，鸟氨酸和赖氨酸），它们基于相似的官能团但分子结构不同而被选择。五个PVA / AA复合物中不同的PVA-AA相互作用导致两种晶体模式，即连续网络（半胱氨酸和赖氨酸）和离散颗粒（谷氨酸，鸟氨酸和天冬氨酸）。然后应用扫描热显微镜来绘制这些复合材料中热传导的分布图。发现晶体周围的界面在声子传输中起主要作用，在声子传输中，聚合物的链受到界面约束作用的极大限制。连续晶体网络建立了一个连续界面，该界面有助于声子转移，而声子散射则发生在离散的晶体结构中。在AVA负载量为8.4 wt％的PVA /半胱氨酸复合物中，观察到显着提高的导热系数〜0.7 W / m·K，与纯PVA相比，提高了170％。强大的PVA-AA分子相互作用和自组织的晶体结构被认为是独特的界面性质和优异的导热性的主要原因。

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Expedited Phonon Transfer in Interfacially Constrained Polymer Chain along Self-Organized Amino Acid Crystals

In this work, poly(vinyl alcohol) (PVA)/amino acid (AA) composites were prepared by a self-organized crystallization process. Five different AAs (cysteine, aspartic acid, glutamic acid, ornithine, and lysine) were selected based on their similar functional groups but different molecular structures. The different PVA–AA interactions in the five PVA/AA composites lead to two crystal patterns, i.e., continuous network (cysteine and lysine) and discrete particles (glutamic acid, ornithine, and aspartic acid). Scanning thermal microscopy is then applied to map the distribution of thermal conduction in these composites. It is found that the interface surrounding the crystals plays a dominating role in phonon transport where the polymer chains are greatly restrained by the interfacial confinement effect. Continuous crystal network builds up a continuous interface that facilitates phonon transfer while phonon scattering occurs in discrete crystalline structures. Significantly improved thermal conductivity of ∼0.7 W/m·K is observed in PVA/cysteine composite with AA loading of 8.4 wt %, which corresponds to a 170% enhancement as compared to pure PVA. The strong PVA–AA molecular interaction and self-organized crystal structure are considered the major reasons for the unique interface property and superior thermal conductivity.

更新日期：2017-03-24

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