Shear-induced unidirectional deposition of bacterial cellulose microfibrils using rising bubble stream cultivation
Shear-induced unidirectional deposition of bacterial cellulose microfibrils using rising bubble stream cultivation
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DOI：
10.1016/j.carbpol.2020.117328
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发表时间：
2021-01-09
影响因子：
11.2
通讯作者：
Kim, Seong H.
中科院分区：
文献类型：
--
作者：
Chae, Inseok;Bokhari, Syed M. Q.;Kim, Seong H.
在结晶纤维素 I 中，所有葡聚糖链均按从还原端到非还原端的顺序排列。因此，各个链的极性被添加，在晶体内形成大偶极子。如果可以设计纤维素晶体的单向排列（平行堆积），那么就有可能利用源自极性晶体结构的材料特性。然而，迄今为止报道的大多数合成后操作方法只能实现单轴双向排列（反平行堆积）。在这里，我们报告了一种通过在培养基中上升的气泡流合成和沉积过程中施加单向剪切应力来诱导细菌纤维素微纤维平行堆积的方法。对准的驱动力通过剪切应力的数学估计来解释。使用非线性光谱技术获得了结晶纤维素 I α 域平行排列的证据。
In crystalline cellulose I, all glucan chains are ordered from reducing ends to non-reducing ends. Thus, the polarity of individual chains is added forming a large dipole within the crystal. If one can engineer unidirectional alignment (parallel packing) of cellulose crystals, then it might be possible to utilize the material properties originating from polar crystalline structures. However, most post-synthesis manipulation methods reported so far can only achieve the uniaxial alignment with bi-directionality (antiparallel packing). Here, we report a method to induce the parallel packing of bacterial cellulose microfibrils by applying unidirectional shear stress during the synthesis and deposition through the rising bubble stream in a culture medium. Driving force for the alignment is explained with mathematical estimation of the shear stress. Evidences of the parallel alignment of crystalline cellulose I alpha domains were obtained using nonlinear optical spectroscopy techniques.