Hyperspectral Imaging of Photonic Cellulose Nanocrystal Films: Structure of Local Defects and Implications for Self-Assembly Pathways.
Hyperspectral Imaging of Photonic Cellulose Nanocrystal Films: Structure of Local Defects and Implications for Self-Assembly Pathways.
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DOI：
10.1021/acsnano.0c05785
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发表时间：
2020-11-24
期刊：
影响因子：
17.1
通讯作者：
Vignolini S
中科院分区：
文献类型：
--
作者：
Zhu B;Johansen VE;Kamita G;Guidetti G;Bay MM;Parton TG;Frka-Petesic B;Vignolini S
纤维素纳米晶(CNCs)可以自发组装成能够在可见光范围内反射圆偏振光的手性向列膜。与许多其他通过自下而上方法获得的光子材料一样，数控薄膜经常会出现缺陷，这些缺陷会对其视觉外观产生很大影响。在这里，我们将光学显微镜和高光谱成像结合起来，研究了光子数控薄膜中缺陷的光学响应，并将其与日益复杂的不连续胆甾相结构的光学模拟进行了比较。薄膜结构的横截面扫描电子显微镜观察指导了模拟参数的选择，并与实验光学图案显示出很好的一致性。更重要的是，它强烈地表明，在溶剂挥发后，碳纳米管的最后一部分自组装并不经历典型的成核和生长途径，而是调幅节点分解，这是迄今为止在铸膜中被忽视的另一种自组装途径，可能会对CNC源的选择和组装条件产生深远的影响。
Cellulose nanocrystals (CNCs) can spontaneously assemble into chiral nematic films capable of reflecting circularly polarized light in the visible range. As many other photonic materials obtained by bottom-up approaches, CNC films often display defects that greatly impact their visual appearance. Here, we study the optical response of defects in photonic CNC films, coupling optical microscopy with hyperspectral imaging, and we compare it to optical simulations of discontinuous cholesteric structures of increasing complexity. Cross-sectional SEM observations of the film structure guided the choice of simulation parameters and showed excellent agreement with experimental optical patterns. More importantly, it strongly suggests that the last fraction of CNCs to self-assemble, upon solvent evaporation, does not undergo the typical nucleation and growth pathway, but a spinodal decomposition, an alternative self-assembly pathway so far overlooked in cast films and that can have far-reaching consequences on choices of CNC sources and assembly conditions.
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影响因子：
29.4
作者：
Frka-Petesic, Bruno;Guidetti, Giulia;Vignolini, Silvia
通讯作者：
Vignolini, Silvia
影响因子：
2.7
作者：
Lettinga, MP;Kang, K;Dhont, JKG
通讯作者：
Dhont, JKG
影响因子：
3.4
作者：
Frka-Petesic, Bruno;Kamita, Gen;Vignolini, Silvia
通讯作者：
Vignolini, Silvia
影响因子：
--
作者：
BERREMAN, DW
通讯作者：
BERREMAN, DW
DOI：
10.3390/ma8115427
发表时间：
2015-11-18
期刊：
Materials (Basel, Switzerland)
影响因子：
--
作者：
Gray DG;Mu X
通讯作者：
Mu X