Designing Dynamic Materials from Dynamic Bonds to Macromolecular Architecture

Abstract

Dynamic polymer materials have characteristic bond exchange behavior, which can be autonomous or in response to external stimuli. Bond exchange in dynamic materials enables numerous applications and enhancement of the material properties. Beyond the precise dynamic chemistries, architectural features of the polymers also play a vital role in governing dynamic material properties. Polymer chain characteristics, crosslink density and distribution, and shapes of the polymers are key architectural features. These architectural features can impact the thermomechanical properties of dynamic polymer materials, including material strength, phase transition and macroscopic flow temperatures, and creep and relaxation behavior, among others. New developments in control over architectural features in dynamic materials have inspired new avenues to design powerful materials with advanced properties. Introducing dynamic and exchangeable bonds can breathe life into polymers by imparting self-healing, enhanced toughness, or adaptability to the material. Synergies between the exchangeable bonds and the polymer’s architectural features can facilitate the dynamic exchange pathways and tune the material’s thermal and mechanical properties. In recent years, numerous dynamic chemistries and architectural variations have been used to develop superior dynamic polymer materials. This article highlights the diversity of dynamic bonds and the polymer architectures used in dynamic polymers, with a focus on how the interplay of dynamic bonds and polymer architecture can be used to develop advanced materials. Finally, this article highlights how judicious choice of the polymer’s architectural features could be used to realize applications of dynamic materials. Introducing dynamic and exchangeable bonds can breathe life into polymers by imparting self-healing, enhanced toughness, or adaptability to the material. Synergies between the exchangeable bonds and the polymer’s architectural features can facilitate the dynamic exchange pathways and tune the material’s thermal and mechanical properties. In recent years, numerous dynamic chemistries and architectural variations have been used to develop superior dynamic polymer materials. This article highlights the diversity of dynamic bonds and the polymer architectures used in dynamic polymers, with a focus on how the interplay of dynamic bonds and polymer architecture can be used to develop advanced materials. Finally, this article highlights how judicious choice of the polymer’s architectural features could be used to realize applications of dynamic materials. crosslinked material containing exchangeable or dynamic covalent bonds, enabling the material to adapt or be reprocessed under appropriate conditions. gradual shape deformation or strain under constant applied stress. materials that contain exchangeable or dynamic bonds that can interchange either autonomically or under stimulus. analysis used to measure a material’s mechanical response as a function of applied strain, temperature, and frequency. a simple analysis that relates molecular weight of polymers to their glass transition temperatures using the Flory-Fox equation proposed by Paul J. Flory in 1950. temperature range of the polymer material where the substrate changes its state from a rigid, glassy stage to a flexible, rubbery stage. the distribution or range of molecular weights present in a polymer sample. constant storage moduli in the lower frequency range or in the region above the glass transition temperature. dissipation of load or stress over time at a constant strain. temperature at which the polymer network becomes effectively frozen and nondynamic and lower temperature for recycling of vitrimer materials. class of covalent networks consisting of thermosetting or similarly behaving polymers that can change their topology by thermally activated bond exchange reactions.