Abstract Inspired by Bouligand-type structure in natural materials featured with helically-aligned reinforcing fibers and superior kink-resistance, we demonstrated an analogous architectural configuration in polypropylene (PP) tube by mean of manipulating helical flow and Ag-coated titanium dioxide (TiO2) fibers. Firstly, the dopamine-assisted immobilization and in situ reduction of Ag ions were completed on the surface of TiO2 fiber, endowing the latter with antibacterial property. Then, the functionalized fibers were introduced into PP matrix, and extruded longitudinally, simultaneously with mandrel rotation, constructing a unique helical flow. Preferred orientation driven by the applied flow assembled the bioinspired Bouligand-like structure with helically-aligned functionalized TiO2 fibers, benefiting torque load bearing and thereby the bulk kink-resistance of polymer tube accompanied by high antibacterial activity. This was exemplified by a substantial increase of 40% in hoop strength with large bacterial inhibition zone in comparison with the pure PP counterpart prepared via convention extrusion. This Bouligand-mimetic alignment strategy can open up a promising possibility of engineering and develop a series of reinforced architectures via simple industrial melt process, satisfying special functionalities and applications unavailable with the other processing technologies.

中文翻译：

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适用于医疗应用的聚丙烯管中离轴银功能化二氧化钛纤维的螺旋流驱动排列

摘要 受具有螺旋排列增强纤维和优异抗扭结性的天然材料中的 Bouligand 型结构的启发，我们通过操纵螺旋流和 Ag 涂层二氧化钛 (TiO2) 在聚丙烯 (PP) 管中展示了类似的结构配置纤维。首先，在TiO2纤维表面完成了多巴胺辅助固定和Ag离子的原位还原，赋予后者抗菌性能。然后，将功能化纤维引入 PP 基体中，纵向挤出，同时与芯轴旋转，构建独特的螺旋流。由应用流驱动的优选取向将仿生的 Bouligand 状结构与螺旋排列的功能化 TiO2 纤维组装在一起，有利于扭矩承载，从而提高聚合物管的整体抗扭结性，同时具有高抗菌活性。与通过常规挤出制备的纯 PP 对应物相比，箍筋强度显着增加 40%，细菌抑制区较大，这就是例证。这种 Bouligand-mimetic 对齐策略可以通过简单的工业熔化过程开辟工程和开发一系列增强架构的有希望的可能性，满足其他加工技术无法提供的特殊功能和应用。