Microfluidics for Two-Dimensional Nanosheets: A Mini Review

Abstract

Since the discovery of graphene, there has been increasing interest in two-dimensional (2D) materials. To realize practical applications of 2D materials, it is essential to isolate mono- or few-layered 2D nanosheets from unexfoliated counterparts. Liquid phase exfoliation (LPE) is the most common technique to produce atomically thin-layered 2D nanosheets. However, low production yield and prolonged process time remain key challenges. Recently, novel exfoliation processes based on microfluidics have been developed to achieve rapid and high yield production of few-layer 2D nanosheets. We review the primary types of microfluidic-based exfoliation techniques in terms of the underlying process mechanisms and the applications of the 2D nanosheets thus produced. The key challenges and future directions are discussed in the above context to delineate future research directions in this exciting area of materials processing.

Revisión sobre la síntesis de grafeno por exfoliación en fase líquida: Mecanismos, factores y técnicas

“…El modelo de devastado en π parece concordar en la tercera etapa del mecanismo de Li, en el sentido que las técnicas de baja velocidad de cizallamiento, como el mezclado de elevada fuerza de corte, presenta bajo rendimiento en la obtención de grafeno monocapa, debido a la dificultad de formar pliegues como se mencionó anteriormente. mientras que las técnicas de gran velocidad de cizallamiento, cercanas a las velocidades propuestas por el trabajo de Botto, como la microfluídica, obtienen buen rendimiento de grafeno monocapa (Choi, 2020). Entonces, podemos deducir que tanto el mecanismo de Paton como el de Botto son correctos para diferentes etapas de la exfoliación, en concordancia con los rendimientos de grafeno monocapa obtenidos experimentalmente.…”

“…el medio líquido a través de un tubo capilar muy pequeño (menor a 100 µm de diámetro) a muy alta velocidad (alrededor de 400 m/s) (Choi, 2020). Un flujo de estas características produce una gran fuerza de corte (10 8 s -1 ) que exfolia casi en su totalidad el material de partida con pocos ciclos (Karagiannidis, 2017).…”

Minireview on Fluid Manipulation Techniques for the Synthesis and Energy Applications of Two-Dimensional MXenes: Advances, Challenges, and Perspectives

“…14,15 Coming from the applications point of view, microfluidics enables a wide variety of practical uses. Its applications range from the synthesis of two-dimensional (2D) materials, 16 flow chemistry, 17 micromixing technology, 18 digital polymerase chain reactions, 19 lab-on-a-chip devices, 20 etc. When the dimensions of the microchannels are reduced, different properties may become enhanced.…”

“…The three digital microfluidic platforms are liquid droplets, liquid marbles, and core–shell beads. , Coming from the applications point of view, microfluidics enables a wide variety of practical uses. Its applications range from the synthesis of two-dimensional (2D) materials, flow chemistry, micromixing technology, digital polymerase chain reactions, lab-on-a-chip devices, etc.…”

Mechanochemical Synthesis of Dispersible Platinum Nanosheets for Enhanced Catalysis in a Microreactor

“…The shear stress in the flow reactor with a uniform diameter depends only on the flow rate and viscosity of the reaction mixture. In particular, with a small change in the flow rate in microreactors, the particles’ size and distribution have been reported to be precisely controlled over a wide range. , For NSs, the synthesis methods using microreactors are divided into top-down exfoliation and bottom-up self-assembly . None of them has used shear stress in microreactors to control the width of NSs yet.…”