Molecular weight is one of important parameters of supramolecular polymers, which affects the physical/chemical properties and processing applications of materials. In this review, we summarize three strategies for characterizing the molecular weight of supramolecular polymers that recently reported by our research group according to the characteristics of supramolecular polymers.

Melt strength, melt viscosity, and foamability of poly(butylene succinate) were improved sustantially by incorporation of vitrimeric network into poly(butylene succinate) through melt polymerization of hydroxyl-terminated poly(butylene succinate) with vanillin derived imine containing compound and hexamethylene diisocyanate using trimethylolpropane as a crosslinking monomer.

We fabricated an extremely tough and self-healing elastomer by introducing dual interactions of acylsemicarbazide hydrogen bonding and Cu2+-Neocuproine coordination simultaneously. The elastomer can achieve a top-notch toughness of 491 MJ/m3. It can also recover almost completely after self-healing at 80℃ for 5 h.

This study reveals that the aromatic dithiocarbamate bonds can undergo reversible dissociation under mild conditions in the absence of a catalyst. The superior dynamic capability of dithiocarbamate bonds enables the reprocessing of crosslinked polydithiourethane while maintaining its original mechanical properties.

The actuation modes and locked shapes of liquid crystal elastomers (LCEs) are adjusted on demand by combining dynamic covalent bonds with cooling-rate-mediated control. This approach provides a novel way for diversifying deformations and enhancing multi-functionality of cutting-edge intelligent devices.

A new design of thermo-fluorochromic carboxylated nitrile butadiene rubber elastomer cross-linked by Eu³⁺-COOH dynamic coordination with deprotonated imidazole as the ancillary ligand is reported. The elastomer shows facile tunable thermo-fluorochromism, exceptional mechanical strength, and high stretchability.

Through rational molecular design and modulation of side chain composition of the copolymers, as an efficient approach, it is quite efficient to achieve diverse phase transition behaviours and adjust phase structures.

By incorporating photo-liquefiable crystalline azobenzene derivative into carboxyl group-grafted SEBS, the resulting composite exhibit orthogonally programmable geometry and moisture-responsive actuating behavior. This is realized by the photo-regulated reversible formation of azobenzene derivative crystalline domains and the gradient reversible conversion between carboxyl and carboxylate group.

Dynamic polysulfide polymers were synthesized from elemental sulfur and epoxide via a mild one-pot strategy. The dynamic polysulfide polymer exhibited multiple dynamic behaviors, including polysulfide metathesism, polysulfide-thiol exchange, and potential transesterification. This work provided a facile strategy for designing dynamic sulfur-rich polymers via a mild synthesis route.

We introduce a straightforward method for fabricating information encryption materials based on a poly(oxime-ester) network with a programmable crystallization temperature induced by UV light. Thus complex patterns and information can be encrypted through different selective regional exposure time and decrypted under specific temperature or cooling time.

We developed a series of ABA-type vitrimers and systematically examined the viscoelastic properties as functions of the length of A moieties and the crosslinker content. We discussed the distinct relaxation mechanisms for vitrimer based on associative exchange reaction and ionomers based on ionic attraction.

Poly(butylene adipate-co-terephthalate) was efficiently upcycled into performance-enhanced dual covalent adaptable networks via chain breaking-crosslinking strategy while maintaining degradability and processability.

We develop a green and sustainable strategy toward closing the loop on carbon fiber reinforced epoxy composites recycling via dynamic dithioacetals. This work presents a pivotal step for sustainable management of end-of-life carbon fiber reinforced epoxy composites, paving the way to a circular economy.

A dynamic covalent poly(imide-imine) polymer with excellent flame retardancy is reported, exhibiting comparable properties to the commercial polyimides, including exceptional mechanical properties, high thermal stability, and outstanding chemical resistance. The plastic can be depolymerized and converted back into the initial pure monomers that can be used to regenerate new-generation plastics.

We introduced the mechanically interlocked cross-links into the supramolecular polymer network to bolster the mechanical robustness. The dually cross-linked network demonstrated enhanced mechanical properties including strength, Young’s modulus and toughness. The additional sliding motion also endowed the material with better performance in energy dissipation and recovery after deformation.

Excellent self-healing and reprocessing performance can be obtained owing to the dynamic benzopyrazole-urea bonds. Phase separation from the aggregation of the benzopyrazole-urea bond induced by the hydrogen bonding and π-π stacking is capable of blocking the dissociation of the benzopyrazole urea bond at low temperature, thus endowing the CANs with anti-creep performance. This hard phase locking strategy provides an efficient approach to design CANs materials with both excellent reprocessing and creep-resistance performance.

Fiber-shaped polymer vitrimer was challenged in this work using commercial maleic anhydride-grafted-high density polyethylene as the matrix and hexanediol as the crosslinker for facile preparation of HDPE vitrimers. The impact of dynamic covalent bonds on the formation of aggregate structures during fiber-shaped vitrimers processing was revealed.

PDMS elastomers with excellent self-healing properties were prepared by introducing aromatic disulfide bonds and multiple hydrogen bonds. PDMS elastomer can realize solid phase recovery and liquid phase recovery. PDMS-based TENG has excellent electrical output performance and self-healing performance.

This study reported the preparation of tough polymer hydrogels through Zr⁴⁺ coordination. Compared to AAla without hydroxyl groups, copolymerization of ASer with AM in water followed by incubation with ZrOCl₂ solution significantly improved the comprehensive mechanical properties of the hydrogels and demonstrated great potential for applications in flexible sensors.

A high-performance adhesive is developed based on epoxy vitrimer in a simple and green method. This epoxy-vitrimer adhesive not only exhibits multi-reusability, but also has good water resistance. This advancement provides a reliable strategy for fabricating multi-reusable adhesive in a sustainable method.

By integrating dynamic lanthanide-Terpyridine coordination, borate ester bonds and hydrogen bondings in poly(vinyl alcohol) matrix, room temperature phosphorescence (RTP) films with multicolor fluorescence, afterglow, enhanced mechanical strength and programmable shape memory were constructed successfully.

The molecular design and synthesis of a new polymerizable spiropyridine compound with a high pKa was reported. Upon covalently incorporated into polymer hydrogels, its molecular photoisomerization leads to macroscale photoactuation of the hydrogels at physiological pH. The independence of this spiropyridine hydrogel from the acidic environment makes it biotolerant and shows excellent biocompatibility.

We have developed the PAxEy supramolecular elastomers based on the thermal growth of ion clusters and dynamic disulfide polymer frameworks, which simultaneously exhibit excellent strength and toughness, admirable self-healing properties, and good biocompatibility.