Nacre-inspired polymeric materials with body heat-responsive shape-memory effect, high optical transparence, and balanced mechanical properties
Nacre-inspired polymeric materials with body heat-responsive shape-memory effect, high optical transparence, and balanced mechanical properties
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具有体热响应形状记忆效应、高光学透明度和平衡机械性能的珍珠质聚合物材料
DOI：
10.1021/acsami.0c15871
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发表时间：
2020
影响因子：
9.5
通讯作者：
Shaoyun Guo
中科院分区：
文献类型：
--
作者：
Bingbing Zeng;Lihua Yang;Jingxian Qin;Yu Zheng;Shaoyun Guo
在这项工作中，受珍珠质分层结构的启发，我们通过增层共挤出制备了聚碳酸丙烯酯(PPC)/热塑性聚氨酯（TPU）交替多层薄膜。基于PPC在37°C左右的玻璃化转变，多层膜表现出出色的体热响应形状记忆效应（SME），具有较高的形状固定率和恢复率（96.1和93.6%），远优于相同成分的常规共连续共混。结果表明，高相连续性和丰富的二维界面是促进应力传递和载荷分布的主要因素。此外，多层膜表现出优越的恢复应力存储能力，形状恢复产生的力允许螺旋在37°C的水中自动膨胀，并有效提升880倍于其重量的负载。与混合材料的不透明度不同，由于透明PPC和TPU的平行组装使光直接穿过薄膜，因此在多层材料中观察到高的光学透明度。同时，类珠粒膜在拉伸过程中发生分层脱粘和分层断裂，拉伸强度比共混物提高90%，断裂伸长率提高70%，屈服应力提高1倍。我们的方法为开发具有优异光学、机械和形状记忆性能的生物启发结构材料铺平了新的道路，这些材料可以扩展到不同的非晶聚合物和弹性体。此外，该材料在生物医学设备和软机器人方面具有很大的应用潜力。
In this work, inspired by the hierarchical architecture of nacre, we have fabricated poly(propylene carbonate) (PPC)/thermoplastic polyurethane (TPU) alternating multilayer films via layer-multiplying coextrusion. Based on the glass transition at around 37 °C of PPC, the multilayer films exhibited an outstanding body heat-responsive shape-memory effect (SME) with high shape fixation and recovery ratios (96.1 and 93.6%), much better than the conventional cocontinuous blend with the same compositions. It was revealed that the high phase continuity and abundantly two-dimensional interfaces both capable of promoting stress transferring and load distribution maximally contributed to the SME. Furthermore, the multilayer films showed a superior recovery stress storage capacity and the force generated by shape recovery allowed automatic expansion of the spiral in 37 °C water and efficient lifting of a load 880 times its weight. Different from the opacity of the blend, a high optical transparence was observed in the multilayers because of the parallel assembly of transparent PPC and TPU enabling light to directly pass through the films. Besides, the nacre-like films had layer debonding and layer stepwise breaking during stretching, resulting in a 90% increase in tensile strength, a 70% increase in elongation at break, and onefold improvement in yield stress, compared with those of the blend. Our approach paves a new way for developing bioinspired structural materials with excellent optical, mechanical, and shape-memory properties, which can be extended to different amorphous polymers and elastomers. Also, the materials presented herein have great potential in applications of biomedical devices and soft robotics.