| 초록 |
Graphene oxide (GO) has become a key component for high-performance carbon-based films or fibers based on its dispersibility and liquid crystallinity in an aqueous suspension. While the superior performance of GO-based films or fibers relies on their alignment at the sub-micrometer level, fine control of the microstructure is often hampered, in particular, under dynamic nature of GO-processing involving shear. Here, we systemically study the structural variation of GO suspensions under shear with unprecedented detail via in-situ rheo-scattering and rheo-POM analysis. The evolution of GO alignment under shear is indeed complex. However, we find the GO alignment can be readily controlled with a dimensionless parameter suggesting a universal orientational diagram. In addition, we reveal the optimal shear rate for the highest degree of alignment, where the resultant graphene fiber attains the improvement of mechanical properties by ~54% without any chemical modification. |
