A new class of quasi-solid polymer electrolytes where both the primary and secondary components of the synthesized semi-interpenetrating polymer networks (semi-IPNs) are comprised of an ether backbone is investigated in detail. The study comprehensively discusses the dependence of physicochemical characteristics and effects on ion conduction behavior for the semi-IPN matrices with reference to the constituent composition, cross-link density, chain length between cross-links, extent of molecular entanglements, charge carrier concentration, and the role of anions. The choice of polyether to be the secondary component resulted in marked improvement in the matrix morphology, enhanced miscibility, better thermal properties, and significant increase in ionic conduction while retaining the quasi-solid nature and film-forming capability of these semi-IPNs. Ionic conductivity of 10–4–10–3 S cm–1 at ambient temperatures, notably without the use of additional plasticization, is achieved with optimization of the semi-IPN matrix as a function of various compositions, content of secondary component, different lithium salts, and electrolyte concentrations. A direct correlation of ionic conductivity to the anion size and ion dissociation such that −N­(CF3SO2)2 – > −ClO4 – > −CF3SO3 – > −I–/–I3 – was observed. The nonlinear temperature dependence of ionic conductivity follows the Vogel–Tammann–Fulcher equation, indicating that the ionic hopping events are strongly coupled with the segmental motions. Evaluation of ion–polymer and polymer–polymer interactions, morphology studies, glass transition temperature, melting temperature, degree of crystallinity, thermal stability, and degradation onset all provide valuable insights into the overall behavior of these semi-IPN electrolytes. These encouraging results favorably indicate their potential applicability in next generation energy conversion and storage devices.

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The present study is a detailed vibrational spectroscopy investigation on the ion−ion and ion−polymer interactions that exist post-solvation or complexation in a new class of quasi-solid polymer electrolytes. Fourier transformed infrared spectra of the synthesized semi-interpenetrating polymer networks (semi-IPNs) matrix of poly(ethyleneoxide)-polyurethane/poly(ethylene glycol) dimethyl ether (P4K-PU/P2 (30:70)) complexed with LiCF 3 SO 3 and LiN(CF 3 SO 2 ) 2 is deconvoluted for three primary stretching zones (ether, carbonyl, and amine) to isolate and identify the ionic species and polymer segments involved. The analysis revealed crucial information pertaining to the localized ion-association behavior, vital clues regarding the competitive interactions present, and important insights into the mechanisms of charge transport. The spectroscopic signatures imply favorable presence of positively charged triple ions or higher aggregate species along with a significant amount of "free" ions and a preferential solubility of the added electrolytes in the amorphous domains of the polymer. Critical salt concentrations C c of EO/Li = 20 and EO/Li = 30 estimated for the LiTf and LiTFSI systems, respectively, are in good agreement with experimentally observed conductivity results. The appreciably high ionic conductivity in these semi-IPN systems could be effectively rationalized considering the nature of ionic dissociation, reassociation, and competitive interaction mechanisms. The availability of a highly disordered matrix with an optimal number of free sites, excellent segmental mobility, appreciable free volume, and finally the existence of adequate labile ionic species, all aids in the high charge transport observed in this new class of quasi-solid electrolytes.

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Semi-interpenetrating polymer networks (semi-IPNs) with significant ionic conductivity (10 S cm at ambient temperature) were studied by vibrational and impedance spectroscopies coupled with advanced analysis procedures. Vibrational spectroscopy recognized the numbers of free ions, ion pairs, ion-polymers and hydrogen bonds within the solid polymer electrolyte matrices (SPE). Electrochemical impedance spectroscopy (EIS) was used to quantify the bulk resistance and bulk relaxation time. The analyses used discrepancy-complexity plots to assess the number of free parameters properly, and EIS was further analyzed using impedance spectroscopy genetic programming (ISGP). Four compositions of PEO-polyurethane/poly(ethylene glycol) dimethyl ether (PEO-PU/PEGDME) were examined with LiClO salt. The polymer electrolyte composition of 30/70 PEO-PU/PEGDME resulted in the lowest relaxation times and the highest ionic conductivity. The best salt concentration was observed at an EO/Li ratio of 30 for the PEO-PU/PEGDME : LiClO (30/70) semi-IPN matrix. Several lithium salts of different anions were examined at an EO/Li ratio of 10, and the ionic conductivity achieved varied in the order -N(CFSO) > -ClO > -(CFSO) > -I/I.

The correlated ion-transport mechanism and its dependence on microscopic phase separation for a new class of quasi-solid semi-IPN electrolytes is probed in considerable detail using temperature-step electrochemical impedance spectroscopy. The response of electrolyte matrices under alternating current perturbation is comprehensively analyzed using a simulated model fit to extract pertinent information relevant to the phase composition and homogeneity, contribution of each phase, interfacial charge-transfer resistance, phase entanglement zones, bulk relaxation time for ionic hopping mechanisms, coupled segmental motions, rate of site reorganization that dictates successful hopping events, and estimates of ionic transport numbers. The normalized complex plane Nyquist plots (ρ′ versus ρ″) show two well-defined regions for bulk (in mid-and high-frequency regions) and electrode− electrolyte interfacial impedance (in low-frequency regions). Rigorous analysis indicates the presence of three microscopic phases in the matrix bulk (pure poly(ethylene oxide)− polyurethane (PEO-PU), pure poly(ethylene glycol) dimethyl ether (PEGDME), and PEO-PU/PEGDME mixed phase) along with the charge-transfer resistance (R ct ) which contribute to the bulk resistance. Spectroscopic plots of complex impedance against frequency (Z″ versus log f) depict Debye peaks, providing an estimate of the bulk relaxation time (τ peak ). Profiles depicting the real component of conductivity (σ′(ω)) as a function of frequency (log f) follow a modified universal power law where the simulated fit results reveal vital information on the site relaxation rates, cumulative favorability for successful hopping events, and predominant charge carrier type. The behavior of the dielectric contributions provides insights into the various ion polarization processes dominant in the high-, mid-, and low-frequency windows of the sweep. These trends were further correlated with our prior evaluation of the physico-chemical properties of the semi-IPN matrices to propose a rational physical model for these complex systems.

Low bioavailability and/or survival at the injury site of transplanted stem cells necessitate its delivery using a biocompatible, biodegradable cell delivery vehicle. In this dataset, we report the application of a porous biocompatible, biodegradable polymer network that successfully delivers bone marrow stem cells (BMSCs) at the wound site of a murine excisional splint wound model. In this data article, we are providing the additional data of the reference article “Porous polymer scaffold for on-site delivery of stem cells – protects from oxidative stress and potentiates wound tissue repair” (Ramasatyaveni et al., 2016) [1]. This data consists of the characterization of bone marrow stem cells (BMSCs) showing the pluripotency and stem cell-specific surface markers. Image analysis of the cellular penetration into PEG–PU polymer network and the mechanism via enzymatic activation of MMP-2 and MMP-13 are reported. In addition, we provide a comparison of various routes of transplantation-mediated BMSCs engraftment in the murine model using bone marrow transplantation chimeras. Furthermore, we included in this dataset the engraftment of BMSCs expressing Sca-1+Lin−CD133+CD90.2+ in post-surgery day 10.

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