Department of Polymer Materials and Engineering, College of Materials and Metallurgy, Guizhou University, Guiyang 550025, China.
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China.
Sci Rep. 2016 Oct 3;6:34572. doi: 10.1038/srep34572.
Despite the enormous potential in bioinspired fabrication of high-strength structure by mimicking the spinning process of spider silk, currently accessible routes (e.g., microfluidic and electrospinning approaches) still have substantial function gaps in providing precision control over the nanofibrillar superstructure, crystalline morphology or molecular orientation. Here the concept of biomimetic nanofibrillation, by copying the spiders' spinning principles, was conceived to build silk-mimicking hierarchies in two-phase biodegradable blends, strategically involving the stepwise integration of elongational shear and high-pressure shear. Phase separation confined on nanoscale, together with deformation of discrete phases and pre-alignment of polymer chains, was triggered in the elongational shear, conferring the readiness for direct nanofibrillation in the latter shearing stage. The orderly aligned nanofibrils, featuring an ultralow diameter of around 100 nm and the "rigid-soft" system crosslinked by nanocrystal domains like silk protein dopes, were secreted by fine nanochannels. The incorporation of multiscale silk-mimicking structures afforded exceptional combination of strength, ductility and toughness for the nanofibrillar polymer composites. The proposed spider spinning-mimicking strategy, offering the biomimetic function integration unattainable with current approaches, may prompt materials scientists to pursue biopolymer mimics of silk with high performance yet light weight.
尽管通过模仿蜘蛛丝的纺丝过程来仿生制造高强度结构具有巨大的潜力，但目前可获得的途径（例如微流控和静电纺丝方法）在提供对纳米纤维超结构、结晶形态或分子取向的精确控制方面仍存在实质性的功能差距。在这里，受仿生纳米纤维化概念的启发，即通过复制蜘蛛的纺丝原理，在两相可生物降解共混物中构建类似丝的层次结构，通过逐步整合拉伸剪切和高压剪切来实现这一目标。在拉伸剪切中引发了纳米级的相分离，以及离散相的变形和聚合物链的预排列，为在后一剪切阶段直接进行纳米纤维化做好了准备。有序排列的纳米纤维具有超低的直径约 100nm，并且“刚柔相济”的系统由纳米晶体域交联，类似于丝蛋白掺杂剂，通过精细的纳米通道分泌出来。多尺度仿生结构的加入为纳米纤维聚合物复合材料提供了强度、延展性和韧性的优异组合。所提出的蜘蛛纺丝仿生策略提供了当前方法无法实现的仿生功能集成，可能促使材料科学家追求具有高性能和轻质的生物聚合物丝的仿生模拟物。
