School of Materials Science and Engineering, International Research Center for Advanced Structural and Biomaterials, Beihang University, Beijing, 100191, China.
State Key Laboratory of Molecular Engineering of Polymers, Laboratory of Advanced Materials and Department of Macromolecular Science, Fudan University, Shanghai, 200433, China.
Soft Matter. 2016 Jul 6;12(27):5926-36. doi: 10.1039/c6sm00019c.
Silks are a family of semi-crystalline structural materials, spun naturally by insects, spiders and even crustaceans. Compared to the characteristic β-sheet crystalline structure in silks, the non-crystalline structure and its composition deserves more attention as it is equally critical to the filaments' high toughness and strength. Here we further unravel the structure-property relationship in silks using Dynamic Mechanical Thermal Analysis (DMTA). This technique allows us to examine the most important structural relaxation event of the disordered structure the disordered structure, the glass transition (GT), in native silk fibres of the lepidopteran Bombyx mori and Antheraea pernyi and the spider Nephila edulis. The measured glass transition temperature Tg, loss tangent tan δ and dynamic storage modulus are quantitatively modelled based on Group Interaction Modelling (GIM). The "variability" issue in native silks can be conveniently explained by the different degrees of structural disorder as revealed by DMTA. The new insights will facilitate a more comprehensive understanding of the structure-property relations for a wide range of biopolymers.
丝绸是一类半结晶结构材料，由昆虫、蜘蛛甚至甲壳类动物自然纺丝而成。与丝绸中典型的β-折叠晶体结构相比，无定形结构及其组成同样值得关注，因为它对纤维的高韧性和高强度同样至关重要。在这里，我们使用动态力学热分析（DMTA）进一步揭示丝绸中的结构-性能关系。该技术使我们能够检查无定形结构中最重要的结构弛豫事件——无定形结构的玻璃化转变（GT），在鳞翅目家蚕和蓖麻蚕以及蜘蛛 Nephila edulis 的天然丝纤维中。基于基团相互作用模型（GIM），对测量得到的玻璃化转变温度 Tg、损耗正切 tanδ 和动态储能模量进行定量建模。DMTA 揭示了无定形结构的不同程度的无序性，这可以方便地解释天然丝中存在的“可变性”问题。新的见解将有助于更全面地了解广泛的生物聚合物的结构-性能关系。
