Programming mechanical properties through encoded network topologies

Abstract

Polymer networks remain an essential class of soft materials. Despite their use in everyday materials, connecting the molecular structure of the network to its macroscopic properties remains an active area of research. Much current research is enabled by advances in modern polymer chemistry providing an unprecedented level of control over macromolecular structure. At the same time, renewed interest in self‐healing, dynamic, and/or adaptable materials continues to drive substantial interest in polymer network design. As part of a special issue focused on research performed in the Polymer Science and Engineering Department at the University of Massachusetts, Amherst, this review highlights connections between macromolecular structure of networks and observed mechanical properties as investigated by the Tew research group.

Phantom Chain Simulations for the Fracture of Energy-Minimized Tetra- and Tri-Branched Networks

“…The effects of structural characteristics of polymer networks on their mechanical properties are a long-standing problem [1][2][3][4][5][6][7]. Apart from the effects of strand length distribution, the established concept is that networks become mechanically inferior according to the amount of included structural defects, such as loops, dangling ends, and entanglements [8][9][10][11][12].…”

Bottlebrush Networks: A Primer for Advanced Architectures

“…[1][2][3] This particular property has been capitalized upon in the form of bottlebrush elastomers (BBEs), where the lack of entanglements allows for supersoft materials (Young's modulus ranging from 10 2 -10 6 Pa) in the absence of diluents (free chain or solvent). [2,[4][5][6][7][8][9][10][11] It should be noted that if the length of side chains becomes larger than some critical amount they will form entanglements with adjacent side chains, ostensibly reducing the impact of this special property of BBNs. [12,13] While BBNs (specifically BBEs) thus far have been primarily synthesized by radical polymerization (RP), additional approaches have surfaced as the BBN architecture has become more broadly studied (Figure 2a-b), albeit with only a limited pool of side chain chemistries (Figure 2c).…”