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.

Advances in harmful organism management are highly demanding due to the toxicity of conventional coating approaches. Exploiting biomimetic superhydrophobicity could be a promising alternative on account of its cost-effectiveness and eco-friendliness. Here, we introduce a facile method to fabricate a robust superhydrophobic coating on a fabric substrate. This is achieved by sequentially spraying TiO2-epoxy resin nanocomposite material and fluorocarbon-silane modified SiO2 nanoparticles (FC-silane SiO2 NPs). The superhydrophobicity is attributed to the nanoparticles constituting a micro/nano hierarchical structure and the fluorocarbon of the modified SiO2 NPs lowering the surface energy. The epoxy resin embedded in the coating layer plays an important role in improving the robustness. The robustness of the superhydrophobic surface is demonstrated by measuring the water slide angle of surfaces that are subject to salty water at 500 rpm stirring condition for up to 13 days. This study focuses on ensuring the superhydrophobicity and robustness of the coating surface, which is preliminary work for the practical management of macrofoulers. Based on this work, we will perform practical harmful organism management in seawater as a second research subject.

Biofouling is a significant problem in the aquaculture and marine shipping industries; thus, various antifouling methods have been developed to prevent the resultant economic losses. In the present study, the superhydrophobic surface of a lotus leaf was bio-mimicked to achieve antifouling. Specifically, fabric substrates with and without superhydrophobic coatings on the surface were installed on the Tongyeong yacht in December 2020 (group A) and April 2021 (group B), and the coverage of the attached invertebrates was recorded every month until August 2021. The coverage of solitary ascidians (Ascidiella aspersa and Ciona robusta) and branching bryozoans (Bugula neritina) was lower on the coated substrates than on the non-coated ones, and coating or non-coating was significantly correlated with the extent of coverage. Superhydrophobic substrates with a low surface energy and micro–nano dual structure may be unsuitable for the attachment of larvae. Therefore, superhydrophobic coating is a more effective and simpler method of antifouling for certain taxa than other antifouling strategies. However, the antifouling effect of the superhydrophobic substrate in group A reduced after 5 months from the first installation; thus, the durability of the antifouling coating should be further improved, and solving this problem remains a major task, necessitating further research.

In order to realize the commercial viability of superhydrophobic surfaces, excellent superhydrophobicity, durability, and multiprocessibility are key aspects. A number of studies regarding improved superhydrophobicity and durability have been extensively reported, while promising strategies aimed at establishing a multiprocessible superhydrophobic coating suspension have been scarcely suggested. In this study, we suggest a facile method that allows the fabrication of the superhydrophobic surface that complies with superhydrophobicity, durability, and multiprocessibility simultaneously. This was achieved by properly engineering the formulation of the coating suspension and coating process. The coating suspension developed could be universally available to a wide range of coating processes including spraying, spin coating, brushing, flow coating, and even inkjet printing. This multiprocessible coating suspension led to facile integration of the superhydrophobic surface, regardless of the material and geometry of substrates. The superhydrophobic surface integrated into glass, the inner wall of tubing, and a printed pattern showed excellent superhydrophobic properties and decent durability. In particular, the patterned superhydrophobic surface exhibited the strong adsorption of fluorescence molecules, which is highly desirable for bioanalysis applications. By accompanying the multiprocessibility, our coating method may be able to facilitate the commercial viability of the superhydrophobic surface and expand its applications in various research fields as well.

Achieving high efficiency in graphene production and printing process simultaneously is challenging, but it needs to be addressed as it is critical for realizing the commercial viability of printed graphene devices. This study successfully substantiates these requirements by significantly improving the efficiency of graphene production and subsequently developing an inkjet-printable graphene ink that enables the rapid formation of the percolation network of graphene flakes. The integration of a flow coil reactor into an ultrasonic bath results in scalable and rapid graphene production, with graphene productivity up to three orders of magnitude higher than conventional liquid-phase exfoliation (LPE), offering the potential that ultrasonic LPE can benefit the scalability and simplicity of graphene production. In addition, the graphene ink, optimized by ink formulation, has a stable high graphene concentration of 3.5 g L–1, resulting in the formation of stable percolation networks of graphene flakes only after two printing passes under optimized printing conditions. The printed graphene patterns are also confirmed to be conformable to various substrates and durable against repeated stretching and bending stress. By ensuring high efficiency in graphene production and inkjet-printable ink preparation, this study would promote the commercialization of graphene production and the resulting printed graphene devices.