Dendrimers and Hyperbranched Polymers - A unique class of polymers

Polymers currently enjoy an enviable position the society of materials, primarily because of their wide range of applications. Polymers owe this proliferation to the long string-like molecular structure, which can twist and turn in parts without leading to a complete disengagement of all intermolecular interactions. Several of the unique properties that polymers exhibit can be traced back to this "molecular" nature of the material.

During the past decade, researchers have designed and synthesized a rather unique class of polymers, namely Dendrimers. Dendrimers, unlike the long string-like linear polymers, are precisely defined macromolecules in which the chain emanates from a central multi-functional core and branches (into two/three) after periodic length intervals. Occurrence of such a periodic branching leads to the generation of a near spherical topology beyond a critical molecular weight or generation. Typically, since the segment length between branch points is small, these polymers possess relatively weak inter-molecular interactions and are devoid of "chain entanglements", both of which are essential to attain good mechanical properties. However, this class of macromolecules and its cousin, namely "hyperbranched polymers" possess several other unique properties, such as low solution/melt viscosity, small-molecule entrapment within the molecular core, unimolecular micelle-like properties, etc.

During the lecture, I will examine this new class of polymers and try to bring out the new-found excitement that has lead to an explosion of research in this area.