Self-Assembly of Hyperbranched Polymers

Abstract

Dendritic polymers, including dendrimers and hyperbranched polymers (HBPs), are the new emerging polymer architectures following the linear, branched, and cross-linking polymers. HBPs, consisting of dendritic units, linear units, and terminal units, are highly branched macromolecules with a three-dimensional dendritic architecture [1–4]. In fact, the hyperbranched structure also widely exists in nature, such as in the lightings, rivers, mountains, trees, corals, glycogens, neurons, and blood vessels. The reason for nature to select hyperbranched structure is certainly related with the unique property advantages originating from such a highly branched structure. As a matter of fact, HBPs have the properties of non/low-entanglement, low viscosity, good solubility, compact structure, and a large number of terminal functional groups. Thus, HBPs can act as processing additives for linear polymers, for improving rheology and flow and for surface modification, which is very useful for processing polymers such as PVC with small temperature windows. In addition, due to the large number of functional groups, HBPs can act as highly efficient crosslinkers or as reactive components in coating and resin formulations. Moreover, HBPs can act as molecular templates to direct the self-assembly and growth of inorganic molecules to produce nanomaterials. Molecular self-assembly is a hot research area in recent year. Generally, the reported precursor molecules used in self-assembly often possess well-defined molecular structures, such as small amphiphiles, dendrimers, and linear block copolymers. Through the self-assembly of these precursors, many elaborate microscopic or mesoscopic supramolecular objects have been observed over the last two decades, including nanoor microscale micelles, vesicles, ribbons, films, fibers, tubules, and so on [5–7]. Compared with these well-defined polymer precursors, HBPs have a rather irregular structure, and thus their self-assembly behaviors have been neglected for a long time. In