End-Group Chemistry and Junction Chemistry in Polymer Science: Past, Present, and Future

Abstract

The current goal in functional polymeric material research is the preparation of polymers with high-fidelity nanoscale self-assembled structures and advanced functionality. Thus, recent research efforts have focused on linking chemistry for the development of tailor-made polymers with desired properties. The design of α- or ω-functionalized telechelic polymers with strongly associative interactions is connected to their unique supramolecular self-assembly behavior in homopolymers and blends. In addition, the end-group modification of block copolymers has shown to alter the polymer morphology radically, resulting in unprecedented property changes arising from confinement effects. This is fascinating because the content of terminal moieties is small compared to that of macromolecular polymer backbones. As an emerging theme in polymer designs and end-group chemistry, the controlled synthesis of polymers with complex architectures and functional linkages has been performed extensively in the past few decades. However, the effects of this linkage on the resultant polymer properties remain elusive and thus will be an important research topic in polymer science in the near future.

Telodendrimers: Promising Architectural Polymers for Drug Delivery

“…In contrast to dendrimers, linear polymers, in general, have PDIs that are often higher than those for dendrimers and dendrons. There are several different methodologies that have been employed to synthesize linear polymers, including anionic, cationic, and radical polymerization [ 4 , 5 ]. For example, (i) PEG is typically prepared from the anionic ring-opening polymerization of epoxides ( Scheme 1 A); (ii) poly(vinyl alcohol) from vinyl acetate, followed by hydrolysis of the ester moieties of the resulting poly(vinyl acetate); (iii) poly(esters), by ring opening reaction of lactones; and (iv) poly(amides) by the condensation of diamines and diesters.…”

“…Block-copolymers were introduced in the early 1950s, and it allowed the synthesis of polymers in which different monomers could be incorporated in blocks or alternating along the linear polymer chain. A variety of methodologies have been developed, including the use of living polymerization, that have allowed the syntheses of linear copolymers with varied backbones of their different blocks [ 4 , 5 ]. The applications of linear polymers in pharmaceutics have been the focus of intense investigations in the past few decades, and one of the early examples was the use of PEG in 1977 [ 106 ].…”

“…Macromolecules continue to offer exciting opportunities to develop functional nano-architectures to address key issues in areas, including biology [ 1 , 2 , 3 ]. There has been tremendous growth in their synthetic articulation from linear block-copolymers to branched and hyperbranched structures [ 4 ]. Amphiphilic diblock co-polymers, being the ones studied more extensively, have played a key role in assembling nanoformulations [ 5 ], in which lipophilic drugs could be physically encaged.…”

Supramolecular Dimerization in a Polymer Melt from Small-Angle X-ray Scattering and Rheology: A Miscible Model System

“…During use they are subjected to fatigue, impact, abrasion and wear that cause the formation of minuscule fractures leading to further larger-scale unrepairable failures and to a limited lifetime. Therefore, transferring self-repair concepts from living matter to synthetic elastomers would represent a great benefit for extending the service intervals of rubber-based components or even for reaching new advanced materials [7][8][9][10][11][12][13]. Designing such novel materials for the future is an interdisciplinary process and requires the joint efforts of microscopic and macroscopic studies of the fundamental underlying principles [14].…”

“…They would tend to microphase separation or micellarization in the melt and introduce new time dependencies in their properties that are linked to the morphology and structure of hydrogen-bonding nanodomains, rather than to the H-bond itself. Many examples of such randomly or terminally functionalized polymers with hydrogen-bonding interactions in solution and bulk state can be found in the literature [11,13,[19][20][21][22][23][24][25][26][27]. In the present context, ionomers also structurally resemble the phase separation [28][29][30].…”