Surface chemistry of two-dimensional layered nanosheets

Two-dimensional (2D) nanosheets have gained its interest since 2004, when Dr. Andre Geim and Dr. Konstantin Novoselov isolated free-standing single layer of graphene (Novoselov et al. 2005). This discovery challenged the theoretical views on 2D materials and showcased the research community about the stability and potential applications of the 2D nanosheets. The stability is governed by the fact that they might have infinitely small fluctuations at low temperatures owing to thermal uctuations (Novoselov 2011). Another possibility is the stabilisation of nanosheets by ripples that extend 2D nanosheets into three-dimensional (3D) objects (Meyer et al. 2007). After isolating free-standing graphene, the work was extrapolated to other inorganic materials giving rise to MoS2, BN, transitional metal dichalcogenides (TMDs), clay, and metal oxides and 2D nanosheets. Since then, there has been much interest in 2D nanosheets. These materials have a restricted dimension, which makes them disparate from its 3D form. One can discriminate this in terms of restriction in size or motion along length and breadth, which gives rise to a flat land (Novoselov 2011). Once graphene was isolated, its properties were significantly different from its counterpart, which could be used in fields like composite materials, electronics, and biomedicine. These plate-like materials could be tailored by stacking on top of each other to obtain layered 3D material, which has huge potential application. In this chapter, we discuss the synthesis, surface chemistry, and biological applications of 2D nanosheets.