Glass-Forming Ability of Polyzwitterions

Abstract

The glass-forming ability of a series of specially synthesized polyzwitterions was studied using fast scanning calorimetry (FSC). Polyzwitterions include those based on the sulfobetaine moiety: sulfobetaine acrylate, ethyl sulfobetaine methacrylate, sulfobetaine vinylimidazole, sulfobetaine 4-vinylpyridine, sulfobetaine methacrylate, and sulfobetaine methacrylamide. FSC was used to investigate the dynamic fragility over a large range of cooling rates, 10−4000 K/s, minimizing thermal degradation of the polyzwitterions. The rate dependence of the limiting fictive temperatures (T f ) was measured and fit to the Williams−Landel−Ferry model, from which the polyzwitterion dynamic fragility was determined for the first time. Dynamic fragility was low, ranging from 41 to 110, depending on the underlying chemical structure, which allows classification of this series of polyzwitterions as moderate to relatively strong polymeric glass formers. Their high glass transition temperatures combined with low fragilities indicates that polyzwitterions are unique among polymeric glass formers. This behavior arises from the formation of interand intrachain dipole−dipole cross-links which causes more dense molecular packing and cohesion.

Solid-State, Single-Ion Conducting, Polymer Blend Electrolytes with Enhanced Li+ Conduction, Electrochemical Stability, and Limiting Current Density

“…The nonmonotonic trend of conductivity vs M n,PLiMTFSI implies that molecular weight is not the sole contributor to the polymer packing frustration. Apart from the molecular weight, , there are other factors impacting the efficiency of polymer chain packing space and the corresponding free volume, such as the dispersity, the backbone rigidity, , the “relative” rigidity of the side group(s) vs the backbone, the molecule symmetry, end-group chemistry, , and inter/intra-molecular interactions. − These factors are typically cross-correlated in polymer systems, and a detailed deconvolution is beyond the scope of this work.…”

Glass Formation in Ring Polymer Melts Having Variable Knot Complexity and Molecular Mass

“…Experimental studies for systems in which the cohesive interaction strength increases through the introduction of charged and polymer groups have likewise indicated a tendency of T g to increase while fragility decreases as the molecular parameter influencing the cohesive interaction strength of the fluid increases. These systems include melts of polyzwitterion materials having increasing charge density, polymer networks with strong hydrogen bonding, − weakly coordinating ionic physical cross-links, and ionomers of increasing charge density, where the decreased fragility is implied qualitatively by a significant broadening of the breadth of the glass transition. The variations of T g and fragility in the knotted ring and many-arm star polymer melts appear to follow this general pattern of behavior.…”

An Injectable Self‐Crosslinked Wholly Supramolecular Polyzwitterionic Hydrogel for Regulating Microenvironment to Boost Infected Diabetic Wound Healing

“…PCBUTA hydrogels in sodium chloride solution swelled more extensively compared with that in deionized water, and the volume‐swelling ratio increased with the increment of sodium chloride solution concentration (Figure 1c), which indicated that PCBUTA hydrogel was partly crosslinked by dipole–dipole interactions of cations and anions in zwitterionic structure. [ 14 ] Subsequently, the as‐prepared PCBUTA hydrogels were immersed in a 5 m urea solution or a precooled mixture solution of 7 wt% NaOH and 12 wt% urea which are commonly used as H‐bonds dissociating agents to verify the H‐bonds interactions. [ 15 ] When the PCBUTA hydrogel was immersed in the 5 m urea solution for 12 h, no significant difference in hydrogel state was found.…”