Gelation with small molecules: From formation mechanism to nanostructure architecture

Abstract

The mechanism of fiber and fiber network formation of small molecular gelling agents is treated on the basis of a generic heterogeneous nucleation model. The formation of a crystallite fiber network can take place via the so-called crystallographic mismatch branching. At very low supersaturations, unbranched fibers form predominantly. As supersaturation increases, small-angle crystallographic mismatch branching occurs at the side face of growth fibers. At very high supersaturations, the so-called wide-angle crystallographic mismatch branching becomes kinetically favorable. Both give rise to the formation of fiber networks, but of different types. Controlling the branching of the nanofibers of small molecular gelatins allows us to achieve the micro/nanostructure architecture of networks having the desired rheological properties. In this regard, the engineering of supramolecular functional materials can be achieved by constructing and manipulating the micro/nanostructure in terms of a "branching creator", or by tuning processing conditions.