State‐of‐the‐Art Analytical Methods for Assessing Dynamic Bonding Soft Matter Materials

Abstract

Dynamic bonding materials are of high interest in a variety of fields in material science. The reversible nature of certain reaction classes is frequently employed for introducing key material properties such as the capability to self-heal. In addition to the synthetic effort required for designing such materials, their analysis is a highly complex--yet important--endeavor. Herein, we critically review the current state of the art analytical methods and their application in the context of reversible bonding on demand soft matter material characterization for an in-depth performance assessment. The main analytical focus lies on the characterization at the molecular level.

Recyclable Crosslinked Polymer Networks via One‐Step Controlled Radical Polymerization

“…Excellent reproduction of room‐temperature tensile properties is also observed in the first and second recycling steps (Table 1, Supporting Information). Because the original and recycled PB/S networks exhibit identical values within error of tensile storage modulus ( E ') in the rubbery plateau region above 60 °C (recall that 3 kg mol −1 PB by itself is a flowing liquid at room temperature) as well as identical, broad glass transition regions, there is highly effective reformation of crosslinks in the recycled, reprocessed sample . The full property retention of the PB/S networks after recycling could be aided by additional crosslinking of unreacted carbon–carbon double bonds in PB repeat units, compensating for any loss of crosslinks through limited irreversible termination reactions of carbon‐centered radicals during reprocessing.…”

Diselenide-Labeled Cyclic Polystyrene with Multiple Responses: Facile Synthesis, Tunable Size, and Topology

“…The topology of the stimuli‐responsive polymer can also be reversibly tuned if the polymer backbone or chain ends were installed by one or more stimuli‐responsive motifs. For example, the reversible Diels–Alder addition between furan and maleimide by heating and cooling switches the topology between linear to cross‐linked form, and this dynamic cross‐linking and de‐crosslinking endows the polymer with self‐healing performance . When a stimuli‐response motif is installed in the backbone of cyclic polymer, the linear‐cyclic topological transformation can be realized by manipulating the polymer concentration and external stimuli.…”

“…For example, the reversible Diels-Alder addition between furan and maleimide by heating and cooling switches the topology between linear to cross-linked form, and this dynamic cross-linking and de-crosslinking endows the polymer with self-healing performance. [10][11][12][13][14] When a stimuli-response motif is installed in the backbone of cyclic polymer, the linear-cyclic topological transformation can be realized by manipulating the polymer concentration and external stimuli. Since there Diselenide-containing polymers have attracted more and more attention due to their redox sensitivity and bioapplication.…”

Thermal Field‐Flow Fractionation for the Investigation of the Thermoresponsive Nature of Star and Linear Polystyrene

“…[10] One possible reason for the slow progress in this area is the lack of suitable characterization platforms that can reliably characterize properties such as molar mass, topology, number of arms, and thermoresponsive properties.To address this need, various columnbased techniques such as size exclusion chromatography (SEC) have been used to characterize star and branched polymers including materials with thermoresponsive properties. [12][13][14][15] However, the characterization of star polymers by SEC can lead to the well-known phenomena of abnormal SEC elution behavior where star polymers of similar hydrodynamic size but different molar masses co-elute. Another limitation of SEC is absorption of analyte molecules onto the stationary phase.…”