Scrolling of supramolecular lamellae in the hierarchical self-assembly of fibrous gels.

Gels are extremely important soft materials with everyday applications in areas such as soaps, lubricants, catalysis, and the oilfield chemistry. Although gels are commonly based on polymers, there is a great deal of interest in small-molecule gelators that aggregate through non-covalent interactions such as hydrogen bonding and π-stacking to give 3D sample-spanning fibrous assemblies. It is very difficult to predict the emergent complexity of gel structure, and gelators are commonly discovered by trial and error. The properties of a gel depend on the structural evolution of its fiber network, but the mechanisms governing fiber growth are not currently understood. In this work, we show that homogeneous gel fibers arise from the scrolling of sheet-like rafts of hydrogen-bonded gelators whenever opposite sides of the sheet possess different surface energies. On the basis of this observation, we propose a general predictive mechanism for gel self-assembly