Block Copolymer Vitrimers

Abstract

In this report, we merge block copolymers with vitrimers in an effort to realize the prospect of higher-order, nanoscale control over associative cross-link exchange and flow. We show the use of controlled polymerization as a vital tool to understand fundamental structure−property effects through the precise control of polymer architecture and molecular weight. Vitrimers derived from self-assembling block copolymers exhibit superior resistance to macroscopic deformation in comparison to their analogs generated from statistical copolymers. Our results suggest that the enhanced creep resistance achieved by control over chain topology in block vitrimers can be used to tune viscoelastic properties. The resistance to macroscopic deformation that arises from a microphase-separated structure in this new class of materials differentiates block vitrimers from their statistical counterparts and introduces the potential of topology-control over viscoelastic flow.

Vitrimers: directing chemical reactivity to control material properties

“…Very recently, Sumerlin, Epps and co-workers implemented phase segregated domains in acrylic based vinylogous urethane vitrimers. 57 In this study, incompatible block copolymer architectures were prepared by RAFT polymerization and the resulting block-derived materials displayed different nanostructural and rheological properties relative to their statistically-derived counterparts.…”

The effect of polarity on the molecular exchange dynamics in imine-based covalent adaptable networks

“…[8][9][10] By stimulating the exchange reactions of the dynamic covalent bonds, for example by introduction of heat or light, a molecular flow is introduced in the material. Several types of bond exchange reactions have been studied over the last decade, such as transesterifications, 1,12 boronic ester exchange, [13][14][15][16] 1,2,3-triazolium exchange, 17,18 diketoenamine exchange, 19,20 (alkyl)urea exchange, [21][22][23] urethane exchange, [24][25][26][27][28] thiol-ene/yne exchange, 29,30 and imine exchange. [31][32][33][34] Individually, each type of bond exchange reaction possesses different dynamics according to the mechanism of the exchange reaction.…”

Implantation of Recyclability and Healability into Cross-Linked Commercial Polymers by Applying the Vitrimer Concept

“…One trend is designed for block copolymer-based materials. As shown in the recent report from Epps and Sumerlin et al [74] and Tang and Guo et al [75], simple AB diblock copolymers can exhibit vitrimeric properties by incorporating associative bond exchange mechanisms in self-assembled A or B domains. Using this strategy, additional positive effects, such as the enhancement of creep resistance, can be attained, because non-vitrimeric domains have a considerably lower mobility than the vitrimeric block.…”

“…A similar approach, i.e., the selective vitrimerization of a component block, is possible for multi-block copolymer systems [76]. In the above report from Epps and Sumerlin et al [74], the investigation of a self-assembled structure has also been carried out by scattering experiments, and such a self-assembled structure was also validated for graft polymer-like vitrimers, according to Ricarte and Leibler et al [77]. In their design, polyethylene chains ("backbone") were linked through relatively long cross-linkers (dioxaborane maleimide, "graft") having a repulsive interaction with the polyethylene.…”