We present systematic, unique linear and nonlinear shear rheology data of an experimentally pure ring polystyrene and its linear precursor. This polymer was synthesized anionically and characterized by interaction chromatography and fractionation at the critical condition. Its weight-average molar mass is 84 kg/mol; i.e., it is marginally entangled (entanglement number Z ≈ 5). Its linear viscoelastic response appears to be better described by the Rouse model (accounting for ring closure) rather than the lattice-animal-based model, suggesting a transition from unentangled to entangled ring dynamics. The failure of both models in the terminal region may reflect the remaining unlinked linear contaminants and/or ring–ring interpenetration. The viscosity evolution at different shear rates was measured using a homemade cone-partitioned plate fixture in order to avoid edge fracture instabilities. Our findings suggest that rings are much less shear thinning compared to their linear counterparts, whereas both obey the Cox–Merz rule. The shear stress (or viscosity) overshoot is much weaker for rings compared to linear chains, pointing to the fact that their effective deformation is smaller. Finally, step strain experiments indicate that the damping function data of ring polymers clearly depart from the Doi–Edwards prediction for entangled linear chains, exhibiting a weak thinning response. These findings indicate that these marginally entangled rings behave like effectively unentangled chains with finite extensibility and deform much less in shear flow compared to linear polymers. They can serve as guideline for further investigation of the nonlinear dynamics of ring polymers and the development of constitutive equations.

The extremely low room-temperature ionic conductivity of solid-state polymer electrolytes (SPEs) ranging from 10-7 to 10-5 S cm-1 seriously restricts their practical application in solid-state lithium metal batteries (LMBs). Herein,...

A new poly(benzyl ether) dendritic organogelator Azo-G3 containing azobenzene in its inner layer was designed and synthesized, and fully characterized. The dendron Azo-G3 was found to be a highly efficient and versatile organogelator toward various apolar and polar organic solvents with the critical gelation concentrations (CGCs) approaching 0.05 wt %, indicating that the dendron belongs to the category of supergelators. Further studies revealed that the intermolecular multiple π−π stacking interactions might be responsible for guiding the self-assembly processes and the gel formation. Most interestingly, these dendritic organogels exhibited multiple stimuli-responsive behaviors upon exposure to environmental stimuli including temperature, sonication, light, and shear stress.

A macroscopic organohydrogel hybrid was prepared by fast adhesion between the hydrogel and organogel which often repel each other. The two original gels were prepared by condensation of two poly­(ethylene glycol) (PEG) gelators in anisole and water, respectively. Reversible acylhydrazone bonds formed in the condensation act as linking points of the polymer networks in the gels. When the two gels were brought into contact, a robust hybridized gel was obtained in 10 min. An emulsion layer formed at the interface between the two gels and dynamic chemistry of acylhydrazone bonding are key factors in rapid adhesion of the two inherently different gels. We hope this finding will enable the development of intelligent soft objects whose macroscopic water and oil phases contain different functional components.

Polymer and ionic liquid (IL) mixtures have attracted an increasing amount of attention due to their unique properties and potential applications. The interactions between poly­(ethylene oxide) (PEO) and imidazolium ILs of different cation alkyl lengths and anion structures have been investigated by measuring melting points (T m), contact angles, and rheological properties. T m of crystalline PEO dramatically decreased when it was blended with ILs. Similarly, the contact angles of different ILs on a PEO surface proportionally decreased. The interaction energy, as calculated from melting point depression using the Flory equation, increased with the length of imidazolium alkyl cations and the size of anions. The different anionic structures had a more significant influence on the interaction energy than the alkyl chain lengths of cations. These trends accorded with the solubility obtained by high-energy X-ray diffraction and swelling ratio measurements of PEO in different ILs [ Asai Asai Macromolecules20134623692375] and the solubility of poly­(methyl methacrylate) in different ILs [ Ueno Ueno Langmuir20143032283235]. The rheological behavior of PEO in three different anionic ILs has also been studied to determine the effect of the anions on PEO conformations. The molecular weight dependence of the intrinsic viscosity of PEO in ILs revealed that the solvent quality of ILs (from poor solvents to good solvents) is highly influenced by anionic structures, which was consistent with the results of the melting point depression and contact angle.

The introduction of optoelectronic functions into viscoelastic polymers can yield highly sophisticated soft materials for biomedical devices and autonomous robotics. However,v iscoelasticity and excellent optoelectronic properties are difficult to achieve because the presence of al arge number of p-conjugated moieties drastically stiffens apolymer. Here,w er eport av ariation of additive-free viscoelastic conjugated polymers (VE-CPs) at room temperature by using an intact p-conjugated backbone and bulky,yet flexible, alkyls ide chains as "internal plasticizers." Some of these polymers exhibit gel-and elastomer-like rheological behaviors without cross-linking or entanglement. Furthermore,b inary blends of these VE-CPs exhibit an ever-seen-before dynamic miscibility with self-restorable and mechanically induced fluorescence color changes.

Bulky but flexible alkyl side chains enable π-conjugated polymers to possess wide-range elastic modulus tuneability, yet consistent red luminescent properties.

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