Synthesis of fish scale and lotus leaf mimicking, stretchable and durable multilayers

Abstract

In general, nature inspired water (lotus leaf mimicking superhydrophobicity in air) and oil (fish scale-inspired superoleophobicity under water) repellent interfaces that are associated with specific physical and chemical parameters, are developed by adopting separate synthesis processes. However, a slight perturbation of the essential topography and chemistry is likely to cause permanent damage to these two distinct nature inspired artificial wettabilites. In this paper, two distinctly characteristic nanomaterials—flexible graphene oxide nanosheets (with grafted primary amine moieties) and amine reactive polymeric nanocomplexes (with residual acrylate groups), are covalently and strategically integrated through a 1,4-conjugate addition reaction for adopting both the fish scale- and lotus leaf inspired ‘stretchable’ and durable wettability that is capable of sustaining: (a) large tensile deformation (100%) multiple times (500 times), and, (b) severe physical/chemical exposures—including physical erosion of the polymeric coating, prolonged exposure to extremes of pH, salinity, ultraviolet radiation, physical manipulations, and so on. The covalent integration of these two different nanomaterials provided a single and simple method for adopting appropriate topography and essential chemical functionality that conferred durable superhydrophobicity and underwater superoleophobicity. The synthesized bio-mimicking interfaces remained water/oil repellent even after stretching the physically damaged multilayer interfaces. Such a durable material is deposited on various substrates, and thus, would be of potential interest for diverse prospective applications in practically relevant harsh applications. Furthermore, there are very few reports of such a single chemical approach that provided durable and stretchable nature inspired superhydrophobicity (in air) and superoleophobicity (under water), in the literature.