Cellulose-based nanocomposites are highly appealing for the development of next-generation sustainable functional materials. Although many advances have been made in this direction, the true potential of fibrillar nanocomposites has yet to be realized because available fabrication approaches are inadequate for achieving precise structural control at the sub-micrometer scale. Here a spray-assisted alignment methodology of cellulose nanofibrils is combined with the layer-by-layer assembly into an additive manufacturing process in which the alignment direction of each cellulose layer is rationally selected to achieve thin films with a helicoidal arrangement of the nanofibrils. The helicoidal structure of the films is verified by measuring the circular dichroism (CD) of the samples. The sign and position of the structural CD peak show that the handedness and the pitch of the chiral structures can be easily tuned by deliberately selecting simple parameters, such as the number of consecutive cellulose layers sprayed in the same direction, and the angle of rotation between successive stacks of layers. To the authors’ knowledge, this approach is unique as it offers the possibility to prepare complex nanocomposite architectures with various nanoscale-controlled sub-structures from different anisometric objects, which is enabling novel designs of composite films with damage-resistant and/or optical filtering functionalities.

中文翻译：

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具有可调手性光学特性的基于自然的螺旋纳米纤维素多室组件

纤维素基纳米复合材料对于开发下一代可持续功能材料非常有吸引力。尽管在这个方向上已经取得了许多进展，但纤维状纳米复合材料的真正潜力尚未实现，因为现有的制造方法不足以实现亚微米尺度的精确结构控制。这里，纤维素纳米纤丝的喷雾辅助排列方法与逐层组装相结合，形成增材制造工艺，其中合理选择每个纤维素层的排列方向，以实现具有纳米纤丝螺旋排列的薄膜。通过测量样品的圆二色性（ CD ）来验证薄膜的螺旋结构。结构CD峰的符号和位置表明，通过故意选择简单的参数，例如沿同一方向喷射的连续纤维素层的数量以及之间的旋转角度，可以轻松调整手性结构的旋手性和螺距。连续的层堆叠。据我们所知，我们的方法是独特的，因为它提供了从不同不等轴物体制备具有各种纳米级控制子结构的复杂纳米复合结构的可能性，这使得具有抗损伤和/或光学过滤功能的复合薄膜的新颖设计成为可能。