3D Printing of Liquid Crystalline Hydroxypropyl Cellulose-toward Tunable and Sustainable Volumetric Photonic Structures
3D Printing of Liquid Crystalline Hydroxypropyl Cellulose-toward Tunable and Sustainable Volumetric Photonic Structures
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DOI：
10.1002/adfm.202108566
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发表时间：
2022-01-13
影响因子：
19
通讯作者：
Vignolini, Silvia
中科院分区：
文献类型：
--
作者：
Chan, Chun Lam Clement;Lei, Iek Man;Vignolini, Silvia
增材制造作为一种灵活的技术，在运输、健康和食品行业的广泛应用中变得越来越重要。然而，为了开发额外的功能，重要的是同时控制跨多个长度尺度的结构化。在3D打印中，这可以通过使用具有固有层次顺序的油墨来实现。液晶系统代表这样一类自组织材料;然而，迄今为止，它们仅用于产生沿挤出方向沿着平行排列的细丝。在这项研究中，羟丙基纤维素（HPC）与原位光交联相结合，产生具有内部螺旋纳米结构的长丝，从而能够直接用墨水书写具有结构色的固体体积物体。通过在交联步骤期间利用HPC的溶致或热致行为，可以在可见光谱范围内调节虹彩颜色，从而允许从相同的原料打印具有不同颜色的物体。此外，通过研究挤出后的微观结构，喷嘴内的剪切的作用被揭示和流变测量模拟喷嘴挤出的基础上提出的机制。最后，通过仅使用可持续的生物聚合物和水，揭示了一条通往环保3D打印的途径。
Additive manufacturing is becoming increasingly important as a flexible technique for a wide range of products, with applications in the transportation, health, and food sectors. However, to develop additional functionality it is important to simultaneously control structuring across multiple length scales. In 3D printing, this can be achieved by employing inks with intrinsic hierarchical order. Liquid crystalline systems represent such a class of self-organizing materials; however, to date they are only used to create filaments with nematic alignment along the extrusion direction. In this study, cholesteric hydroxypropyl cellulose (HPC) is combined with in situ photo-crosslinking to produce filaments with an internal helicoidal nanoarchitecture, enabling the direct ink writing of solid, volumetric objects with structural color. The iridescent color can be tuned across the visible spectrum by exploiting either the lyotropic or thermotropic behavior of HPC during the crosslinking step, allowing objects with different colors to be printed from the same feedstock. Furthermore, by examining the microstructure after extrusion, the role of shear within the nozzle is revealed and a mechanism proposed based on rheological measurements simulating the nozzle extrusion. Finally, by using only a sustainable biopolymer and water, a pathway toward environmentally friendly 3D printing is revealed.