Novel Gas-Driven\nMilli-Channel Shear Device: Numerical\nSimulation and Experimental Exfoliation of 2D Materials

Two-dimensional (2D) materials have exhibited great potential\nfor\nvarious applications due to their remarkable properties. Fluid dynamics-assisted\nliquid-phase exfoliation is a promising strategy for the scalable\nproduction of 2D materials at a low cost. However, the production\nrate is significantly constrained due to the confinement of the high-shear\nzone to specific local regions in traditional fluid dynamics devices.\nTo this end, we designed a novel gas-driven milli-channel shear device\n(GMSD). In this work, shear characteristics of the GMSD were studied\nusing computational fluid dynamics numerical simulation and verified\nby high-speed imaging. The exfoliation capability of 2D materials\nwith the GMSD was investigated through experimental production of\ngraphene and MoS<sub>2</sub>. The results indicated that high shear\ncan be achieved uniformly across the entire GMSD. The average wall\nshear stress and internal shear rate of the milli-channel reached\n650.2 Pa and 1.94 × 10<sup>5</sup> s<sup>–1</sup>, respectively.\nThe shear stress for 95% of the particles significantly exceeded the\nminimum shear stress threshold of 146 Pa. A higher gas–liquid\nvelocity ratio (<i>k</i>) enhances exfoliation efficiency,\nand a sharp outlet demonstrates greater favorability for the exfoliation.\nThe GMSD, with its simple structure, presents an efficient alternative\nfor the scalable production of 2D materials.