50th Anniversary Perspective: Polymers with Complex Architectures

Abstract

The scope of this Perspective is to highlight innovative contributions in the synthesis of well-defined complex macromolecular architectures and to emphasize the importance of these materials to polymer physical chemistry, physics, theory, and applications. In addition, this Perspective tries to enlighten the past and show possible pathways for the future. Among the plethora of polymerization methods, we briefly report the impact of the truly living and controlled/ living polymerization techniques focusing mainly on anionic polymerization, the mother of all living and controlled/living polymerizations. Through anionic polymerization well-defined model polymers with complex macromolecular architectures having the highest molecular weight, structural and compositional homogeneity can be achieved. The synthesized structures include star, comb/graft, cyclic, branched and hyberbranched, dendritic, and multiblock multicomponent polymers. In our opinion, in addition to the work needed on the synthesis, properties, and application of copolymers with more than three chemically different blocks and complex architecture, the polymer chemists in the future should follow closer the approaches Nature, the perfect chemist, uses to make functional complex macromolecular structures by noncovalent chemistry. Moreover, development of new analytical methods for the characterization/purification of polymers with complex macromolecular architectures is essential for the synthesis and properties study of this family of polymeric materials.

When convergent syntheses of graft block copolymers diverge: The treachery of chemical images

“…Polymer composition and architecture impact the physical properties of polymers . For example, linear triblock copolymers comprised a soft midblock and hard exterior blocks are significantly tougher and more elastic than their diblock equivalents.…”

Radical Polymerization of Alkyl 2-Cyanoacrylates

“…With the latter conventional anionic polymerizations stringent experimental conditions, including inert atmospheres and glove boxes are a requirement [33,34]. It is noteworthy that the recent advances in the synthesis of well-defined complex macromolecular architectures using anionic polymerizations (including star, comb/graft, cyclic, branched, hyperbranched, dendritic and multi-block multi-component polymers [35]) are yet to be achieved with the highly reactive monomer subject of this review.…”

Ring and Linear Copolymer Blends under Confinement

“…For example, dendrimers and dendritic polymers (a subset of hyperbranched polymers) finds application ranging from coating to drug and gene delivery due to its unique structural propertiesglobular architecture and response to different solvent conditions. [1,2] Of much recent interest is the ring(R) or cyclic polymer, a topologically constrained polymer chain made by closing the chain ends of a linear polymer, [3][4][5] which is not only relevant in physics (e.g., in understanding collapse of polymer gel), but also in biology (e.g., as a model system for chromatin folding and existence of chromosome territories). [6,7] Theory and experimental studies on ring polymer melts show that topological constraints influence both statics and dynamics.…”