Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States.
School of Materials Engineering, Purdue University, Neil Armstrong Hall of Engineering, 701 West Stadium Avenue, West Lafayette, Indiana 47907-2045, United States.
J Am Chem Soc. 2020 Mar 11;142(10):4762-4768. doi: 10.1021/jacs.9b13356. Epub 2020 Feb 27.
Developing future high performance adhesives is predicated upon achieving properties including strength and ductility. However, designing tough materials that are simultaneously strong and soft is usually contradictory in nature. Biological materials including shells and wood achieve impressive toughness by using weak bonds to connect larger structures at several length scales. Here, we show that this toughness design approach can be applied to synthetic adhesives. A biomimetic adhesive polymer, poly(catechol-acrylic acid), was examined in conjunction with several compounds containing two organic functional groups. In a typical example, the diol ethylene glycol decreased the overall system modulus. Performance was seen to increase significantly. Spectroscopic and physical methods indicated that these bifunctional additives created an interpolymeric network of weak hydrogen bonds. Material toughness was enhanced when breakable bonds were available to dissipate mechanical stresses while leaving the surrounding matrix intact. These discoveries illustrate how a biological materials strategy of interplay between strength and ductility can be achieved with sacrificial bonds in an adhesive. Such an approach may be a general principle applicable to designing higher performance electronics, transportation, and aerospace systems.
开发未来的高性能粘合剂需要实现强度和延展性等性能。然而，设计既强又软的坚韧材料通常在本质上是相互矛盾的。包括贝壳和木材在内的生物材料通过使用弱键将较大的结构连接在几个长度尺度上来实现令人印象深刻的韧性。在这里，我们表明这种韧性设计方法可以应用于合成粘合剂。我们研究了一种仿生粘合剂聚合物聚（邻苯二酚-丙烯酸），并结合了几种含有两个有机官能团的化合物。在一个典型的例子中，二醇乙二醇降低了整个系统的模量。性能显著提高。光谱和物理方法表明，这些双官能添加剂在弱氢键之间形成了一种互穿聚合物网络。当有可断裂的键来耗散机械应力时，材料韧性得到了增强，同时周围的基质保持完整。这些发现说明了在粘合剂中使用牺牲键如何实现生物材料的强度和延展性之间的相互作用策略。这种方法可能是一种普遍适用于设计更高性能的电子、运输和航空航天系统的原则。
