Hou Xunan, Chen Shuai, Koh J Justin, Kong Junhua, Zhang Yong-Wei, Yeo Jayven C C, Chen Haiming, He Chaobin
Department of Materials Science and Engineering, National University of Singapore (NUS), 9 Engineering Drive 1, Singapore 117575, Singapore.
Institute of High Performance Computing, Agency for Science, Technology, and Research (A*STAR), 1 Fusionopolis Way, Connexis, Singapore 138632, Singapore.
ACS Macro Lett. 2021 Apr 20;10(4):406-411. doi: 10.1021/acsmacrolett.0c00844. Epub 2021 Mar 12.
Polymer blends with synergetic performance play an integral part in modern society. The discovery of compatible polymer systems often relies on strong chemical interactions. By contrast, the role of entropy in polymers is often neglected. In this work, we show that entropy effect could control the phase structure and mechanical behaviors of polymer blends. For weakly interacting polymer pairs, the seemingly small mixing entropy favors the formation of nanoscale cocontinuous structures. The abundant nanointerfaces could initiate large plastic deformations by crazing or shear, thus, transforming brittle polymers (elongation < 9%) into superductile materials (elongation ∼ 146%). The resultant polymer blends display high transparency, strength (∼70 MPa), and toughness (∼60 MJ/m) beyond most engineering plastics. The principle of entropy-driven blends may also be applied in other polymer systems, offering a strategy to develop mechanically robust bulk polymeric materials for emerging applications such as biomedicine and electronics.
具有协同性能的聚合物共混物在现代社会中发挥着不可或缺的作用。相容性聚合物体系的发现通常依赖于强烈的化学相互作用。相比之下，熵在聚合物中的作用常常被忽视。在这项工作中，我们表明熵效应可以控制聚合物共混物的相结构和力学行为。对于弱相互作用的聚合物对，看似微小的混合熵有利于形成纳米级共连续结构。丰富的纳米界面可以通过 crazing 或剪切引发大的塑性变形，从而将脆性聚合物（伸长率 < 9%）转变为超韧性材料（伸长率 ∼ 146%）。所得的聚合物共混物具有高透明度、强度（∼70 MPa）和韧性（∼60 MJ/m³），超越了大多数工程塑料。熵驱动共混物的原理也可应用于其他聚合物体系，为开发用于生物医学和电子等新兴应用的机械性能强大的块状聚合物材料提供了一种策略。
