State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University , Hangzhou 310027, China.
Department of Polymer Science and Engineering, Zhejiang University , Hangzhou 310027, China.
ACS Nano. 2017 May 23;11(5):4777-4784. doi: 10.1021/acsnano.7b01089. Epub 2017 Apr 27.
Through designing hierarchical structures, particularly optimizing the chemical and architectural interactions at its inorganic/organic interface, nacre has achieved an excellent combination of contradictory mechanical properties such as strength and toughness, which is highly demanded yet difficult to achieve by most synthetic materials. Most techniques applied to develop nacre-mimetic composites have been focused on mimicking the "brick-and-mortar" structure, but the interfacial architectural features, especially the asperities and mineral bridges of "bricks", have been rarely concerned, which are of equal importance for enhancing mechanical properties of nacre. Here, we used a modified bidirectional freezing method followed by uniaxial pressing and chemical reduction to assemble a nacre-mimetic graphene/poly(vinyl alcohol) composite film, with both asperities and bridges introduced in addition to the lamellar layers to mimic the interfacial architectural interactions found in nacre. As such, we have developed a composite film that is not only strong (up to ∼150.9 MPa), but also tough (up to ∼8.50 MJ/m), and highly stretchable (up to ∼10.44%), difficult to obtain by other methods. This was all achieved by only interfacial architectural engineering within the traditional "brick-and-mortar" structure, without introducing a third component or employing chemical cross-linker as in some other nacre-mimetic systems. More importantly, we believe that the design principles and processing strategies reported here can also be applied to other material systems to develop strong and stretchable materials.
通过设计分层结构，特别是优化其无机/有机界面的化学和建筑相互作用，珍珠母实现了强度和韧性等矛盾机械性能的优异结合，这是大多数合成材料所需要但难以实现的。大多数用于开发珍珠母仿生复合材料的技术都集中在模仿“砖-泥”结构，但界面建筑特征，特别是“砖”的粗糙度和矿物桥，对于增强珍珠母的机械性能同样重要。在这里，我们使用改进的双向冷冻法，然后进行单向压制和化学还原，组装了一种珍珠母仿生石墨烯/聚乙烯醇复合膜，除了层状结构外，还引入了粗糙度和桥接结构，以模拟珍珠母中发现的界面建筑相互作用。通过这种方式，我们开发出了一种不仅强度高（高达约 150.9 MPa）、韧性好（高达约 8.50 MJ/m）、拉伸性好（高达约 10.44%）的复合膜，这是其他方法难以实现的。这一切都是通过传统的“砖-泥”结构内的界面建筑工程实现的，没有像其他一些珍珠母仿生系统那样引入第三组分或使用化学交联剂。更重要的是，我们相信这里报道的设计原则和加工策略也可以应用于其他材料系统，以开发具有高强度和拉伸性的材料。
