Hong Dongpyo, Sattorov Matlabjon, Jeon Ok Sung, Lee Se Hun, Park Gun-Sik, Yoo Young Joon, Park Sang Yoon
Advanced Institute of Convergence Technology, Seoul National University Suwon-si 16229 Republic of Korea
Center for THz-Driven Biomedical Systems, Department of Physics and Astronomy, Institute of Applied Physics, College of Natural Sciences, Seoul National University Seoul-si 08826 Republic of Korea
Nanoscale Adv. 2024 Aug 28;6(21):5306-12. doi: 10.1039/d4na00328d.
The aqueous dispersibility and processability of graphene oxide (GO) are pivotal for various applications, including the fluid assembly of macroscopic materials and nanofluidic systems. Despite the widespread utilization of ultrasonic treatment to achieve homogeneous dispersions, the rheological changes of GO during sonication have remained relatively unexplored, leading to conflicting research findings. In this study, we demonstrate that the viscoelastic evolution of GO can significantly differ under ultrasonic fragmentation depending on the balance between repulsion force and attraction force at the initial state before fragmentation. When electrostatic repulsion is in delicate equilibrium with attractive forces, gelation occurs under ultrasonic fragmentation, leading to increased viscosity under sonication. Conversely, when electrostatic repulsion predominates, viscosity decreases during sonication. This study reconciles conflicting observations on the rheological evolution of GO dispersions under ultrasonic fragmentation and provides valuable guidance and insights for the rheological engineering of GO colloidal systems.
氧化石墨烯（GO）的水分散性和可加工性对于各种应用至关重要，包括宏观材料的流体组装和纳米流体系统。尽管广泛使用超声处理来实现均匀分散，但超声处理过程中GO的流变学变化仍未得到充分研究，导致研究结果相互矛盾。在本研究中，我们证明，根据破碎前初始状态下排斥力和吸引力之间的平衡，GO在超声破碎下的粘弹性演变可能会有显著差异。当静电排斥力与吸引力处于微妙平衡时，超声破碎会导致凝胶化，从而使超声处理过程中的粘度增加。相反，当静电排斥力占主导时，超声处理过程中粘度会降低。本研究调和了关于超声破碎下GO分散体流变学演变的相互矛盾的观察结果，并为GO胶体系统的流变学工程提供了有价值的指导和见解。
