Novel Gas-Driven Milli-Channel Shear Device: Numerical Simulation and Experimental Exfoliation of 2D Materials

Abstract

Two-dimensional (2D) materials have exhibited great potential for various applications due to their remarkable properties. Fluid dynamics-assisted liquid-phase exfoliation is a promising strategy for the scalable production of 2D materials at a low cost. However, the production rate is significantly constrained due to the confinement of the high-shear zone to specific local regions in traditional fluid dynamics devices. To this end, we designed a novel gas-driven milli-channel shear device (GMSD). In this work, shear characteristics of the GMSD were studied using computational fluid dynamics numerical simulation and verified by high-speed imaging. The exfoliation capability of 2D materials with the GMSD was investigated through experimental production of graphene and MoS2. The results indicated that high shear can be achieved uniformly across the entire GMSD. The average wall shear stress and internal shear rate of the milli-channel reached 650.2 Pa and 1.94 × 105 s–1, respectively. The shear stress for 95% of the particles significantly exceeded the minimum shear stress threshold of 146 Pa. A higher gas–liquid velocity ratio (k) enhances exfoliation efficiency, and a sharp outlet demonstrates greater favorability for the exfoliation. The GMSD, with its simple structure, presents an efficient alternative for the scalable production of 2D materials.