Zidek Jan, Milchev Andrey, Jancar Josef
Advanced Polymers and Composites, Central European Institute of Technology (CEITEC), Brno University of Technology, Brno, Czechia.
Institute of Physical Chemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria.
Front Chem. 2020 Feb 26;8:120. doi: 10.3389/fchem.2020.00120. eCollection 2020.
In an effort to study natural fiber formation, such as, e.g., spider silk, we present a model, which is capable of forming biomimetic fibrillar nanostructure from a hydrogel micellar network. The latter consists of interacting atomic groups which form cores of micelles, and of flexible chains forming the shells of the micelles. Micelles are connected in a compact network by linearly stretched chains. The structural elements of the network can be transformed during deformation from micellar into fibrillary type and their evolution is found to depend significantly on strain rate. Our model suggests a set of conditions suitable for the formation of nanostructured fibrillar network. It demonstrates that a fibrillar structure is only formed upon sufficiently fast stretching while, in contrast, the micellar gel structure is preserved, if the material is pulled slowly. We illustrate this key aspect by a minimalistic model of only four chains as part of the whole network, which provides a detailed view on the mechanism of fibril formation. We conclude that such a simplified structure has similar functionality and is probably responsible for the formation of nano-structured molecular fibrils in natural materials.
为了研究天然纤维的形成，例如蜘蛛丝，我们提出了一个模型，该模型能够从水凝胶胶束网络中形成仿生纤维状纳米结构。后者由形成胶束核心的相互作用原子基团和形成胶束外壳的柔性链组成。胶束通过线性拉伸链连接成紧密网络。网络的结构元素在变形过程中可以从胶束类型转变为纤维状类型，并且发现它们的演化显著依赖于应变速率。我们的模型提出了一组适合形成纳米结构纤维网络的条件。它表明，只有在足够快的拉伸时才会形成纤维状结构，相反，如果材料缓慢拉伸，则胶束凝胶结构会得以保留。我们通过仅作为整个网络一部分的四条链的简约模型来说明这一关键方面，该模型提供了关于纤维形成机制的详细视图。我们得出结论，这种简化结构具有相似的功能，并且可能是天然材料中纳米结构分子纤维形成的原因。
