Freeze-Casting Produces a Graphene Oxide Aerogel with a Radial and Centrosymmetric Structure
Freeze-Casting Produces a Graphene Oxide Aerogel with a Radial and Centrosymmetric Structure
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DOI：
10.1021/acsnano.8b01747
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发表时间：
2018-06-01
期刊：
影响因子：
17.1
通讯作者：
Ruoff, Rodney S.
中科院分区：
文献类型：
--
作者：
Wang, Chunhui;Chen, Xiong;Ruoff, Rodney S.
We report the assembly of graphene oxide (G-O) building blocks into a vertical and radially aligned structure by a bidirectional freeze-casting approach.水结晶成冰，将 G-O 片组装成一种结构，即 GO 气凝胶，其局部结构模仿涡轮叶片。该气凝胶中的厘米级辐射结构具有许多通道，其宽度随着距中心的距离而增加。 This was achieved by controlling the formation of the ice crystals in the aqueous G-O dispersion that grew radially in the shape of lamellae during freezing. Because the shape and size of ice crystals is influenced by the G-O sheets, different additives (ethanol, cellulose nanofibers, and chitosan) that can form hydrogen bonds with H2O were tested and found to affect the interaction between the G-O and formation of ice crystals, producing ice crystals with different shapes.还获得了具有螺旋图案的G-O/壳聚糖气凝胶。 After chemical reduction of G-O, our aerogel exhibited elasticity and absorption capacity superior to that of graphene aerogels with "traditional" pore structures made by conventional freeze-casting.这种方法可以扩展到许多其他配置，并且应该扩大 G-O（以及还原 G-O 和“石墨烯”）气凝胶的使用。
We report the assembly of graphene oxide (G-O) building blocks into a vertical and radially aligned structure by a bidirectional freeze-casting approach. The crystallization of water to ice assembles the G-O sheets into a structure, a GO aerogel whose local structure mimics turbine blades. The centimeter-scale radiating structure in this aerogel has many channels whose width increases with distance from the center. This was achieved by controlling the formation of the ice crystals in the aqueous G-O dispersion that grew radially in the shape of lamellae during freezing. Because the shape and size of ice crystals is influenced by the G-O sheets, different additives (ethanol, cellulose nanofibers, and chitosan) that can form hydrogen bonds with H2O were tested and found to affect the interaction between the G-O and formation of ice crystals, producing ice crystals with different shapes. A G-O/chitosan aerogel with a spiral pattern was also obtained. After chemical reduction of G-O, our aerogel exhibited elasticity and absorption capacity superior to that of graphene aerogels with "traditional" pore structures made by conventional freeze-casting. This methodology can be expanded to many other configurations and should widen the use of G-O (and reduced G-O and "graphenic") aerogels.