On-surface polymerization - a versatile synthetic route to two-dimensional polymers

Two-dimensional (2D) polymers are novel covalent sheet materials with promising properties, but also great synthetic challenges. The inadequacy of traditional wet chemical synthesis calls for new synthetic paradigms. In this respect, employing surfaces as inherently 2D reaction venues appears an adequate choice and has recently already yielded encouraging results. Polymerization at air - liquid and liquid - liquid interfaces has been reported from time to time over the last decades, whereas recent efforts on solid surfaces are less traditional. In either case, both movement and coupling of monomers are already confined in two dimensions at interfaces or on surfaces. Accordingly, this approach naturally affords low-dimensional reaction products. To achieve 2D reticulation, monomers are functionalized with multiple reactive groups of the same or a different kind, whereby their number and stereochemical arrangement predefines the ideal structure of the resulting 2D polymer. This perspective article exemplifies different approaches, i.e. types of surfaces, coupling chemistry and activation schemes, to employ surfaces for novel synthetic routes for the bottom-up synthesis of 2D polymers. (c) 2015 Society of Chemical Industry