Master of Science in Materials Science and Engineering (MSMSE), Wright State University, 2024, Materials Science and Engineering

The abundance and the cost-effectiveness of sodium resources have made sodium-ion batteries (SIBs) viable alternatives to lithium-ion batteries. Developing low-cost and high-performance electrolytes is one of the key areas for the advancement of SIB technology. The highly conductive liquid or solid electrolytes have the potential for practical sodium-ion battery applications. Long-term stability, alternative polymers, and full-cell integrations are other avenues that need further research to improve scalability and performance for SIBs. This research covers preparing and evaluating liquid and polymer electrolytes, with a focus on ionic conductivities. Liquid electrolytes were prepared by the dissolution of different sodium salts including NaCl, Na2S, Na2SO3, and NaF in methanol, water, DMF (dimethyl formamide), n-propanol, and DMSO (dimethyl sulfoxide) solvents, in a concentration range from 0.01 M to 0.1 M. It is aimed to investigate the impacts of the solubility, polarity, and concentration on the ionic conductivities. Polymer electrolytes were prepared using the solvent casting technique. The films contained NaCl as the salt and PEO (polyethylene oxide) as the polymer host. The impacts of the two solvents, methanol and DMF, with and without plasticizer EC (ethylene carbonate) on the ionic conductivity of the polymer electrolytes were analyzed. The study validates that optimizing solvent and additive selection are paramount in developing high-performance electrolytes for SIBs.

Committee: Hong Huang Ph.D. (Advisor); Ahsan Mian Ph.D. (Committee Member); Henry D. Young Ph.D. (Committee Member) Subjects: Engineering; Materials Science

Master of Science, University of Akron, 2023, Mechanical Engineering

All-solid-state lithium batteries (ASSLBs) using argyrodite electrolyte materials have shown promise for applications in electric vehicles (EVs). However, understanding the effects of processing parameters on the ionic conductivity of these electrolytes and performance of full solid-state cells is crucial for optimizing battery performance and manufacturing methods. This study investigates the influence of electrolyte operating temperature, operating pressure, pelletization pressure, and pelletizing temperature on the ionic conductivity of Li6PS5Cl0.5Br0.5 argyrodite electrolyte (AmpceraTM, D50=10 µm) as well as how pelletizing temperature impacts a full solid-state cell's cycle life. A specially designed test cell is employed for the experimental measurements, allowing for controlled pelletization and testing within the same tooling. The results demonstrate the significant impact of the four parame-ters on the ionic conductivity of the argyrodite electrolyte. The electrolyte operating temperature has a more pronounced effect than operating pressure, and pelletizing temperature exerts a greater influence than pelletizing pressure. This study provides results that aid in understanding the interplay between these parameters and achieving desired conductivity values. It also establishes a baseline for the maximum pelletizing temperature before undesirable degradation of electrolyte occurs. By manipulating the pelletizing pressure, operating pressure, and pelletizing temperature, battery engineers can achieve the desired conductivity for specific applications. The findings emphasize the need to consider operating conditions to ensure satisfactory low-temperature performance, particularly for EVs. Overall, this study provides valuable insights into processing and operating conditions for ASSLBs utilizing Li6PS5Cl0.5Br0.5 argyrodite electrolyte.

Committee: Siamak Farhad (Advisor); Christopher DellaCorte (Committee Member); Alper Buldum (Committee Member); Rashid Farahati (Advisor) Subjects: Energy; Engineering; Materials Science; Mechanical Engineering

Doctor of Philosophy (PhD), Ohio University, 2021, Chemical Engineering (Engineering and Technology)

Incorporation of potassium bifluoride (KF-HF) as an additive to lithium-halide electrolyte for thermal batteries was investigated. Results indicated that it is feasible to maintain a relatively high ionic conductivity at temperatures (250-300 C) lower than current thermal battery electrolytes (400-550 C). Mixtures of lithium fluoride and potassium bifluorides with the 40-60 wt.% provided the best ionic conductivity at 260 C. Ceramic felts are shown to be an effective alternative to widely used MgO. One of the major benefits of ceramic felts is their high porosity and low weight. LiSi/FeS2 thermal cells with YSZ and Al2O3 ceramic felt electrolyte/separators reported specific energy of 58.47 Wh kg-1 and 43.96 Wh kg-1. Pellet design pyrite (FeS2) cathodes for thermal batteries usually have low electronic conductivity. A new cathode design was developed using iron particles. By adding 11 wt.% Fe particles to the cathode the ohmic polarization was reduced by 17.5% while the available capacity was increased by 78% over the cell with traditional cathode pellet with no electrically conductive particle additives.

Committee: Gerardine Botte (Advisor); Valerie Young (Advisor) Subjects: Chemical Engineering; Energy; Engineering

Master of Science, University of Akron, 2020, Polymer Engineering

The present thesis focuses on elucidation on the role of ionic liquid in polymer electrolyte membranes for energy harvesting and storage. Recently, research interest on ionic liquid-in-salt has gained considerably due to its high thermal stability and ionic conductivity, which has potential as a replacement for the facile organic solvent electrolyte in lithium ion battery. The status of emerging lithium ion batteries has been reviewed in Chapter I, followed by Materials and Methods including physical and electrochemical characterizations in Chapter II and Chapter III. In Chapter IV, the polymer electrolyte membrane (PEM) containing liquid polyether sulfide (PES, Thiokol) was fabricated via thiol-ene click reaction with poly (ethylene glycol) diacrylate (PEGDA) with the aid of a photo-initiator under UV light for photocuring. The so-called solid polymer electrolyte membrane thus formed is an isotropic, completely amorphous, transparent, and flexible solid-state membrane. The ionic conductivity of (PES-co-PEGDA/HMIMTFSI) was determined by AC impedance as a function of thiol (SH) content which served as flexible side chains. The ionic liquid (HMIMTFSI) can dissociate Li ions from its salt and also plasticize the PEM network. As a result, the increasing amount of Thiokol and HMIMTFSI can both sevred as the ionizers to enhance the ionic conductivity. The flexoelectric coefficients (μ) of various PEMs-(TK-co-PEGDA/HMITFSI) were determined under intermittent square wave and dynamic oscillatory bending modes by using Dynamic Mechanical Analyzer (DMA) combined with Solartron Potentiostat/Galvanostat. The present PEM (TK-co-PEGDA/HMIMTFSI) exhibited larger flexoelectric coefficient than those of conventional insulating materials such as ferroelectric ceramics and bent-core nematic liquid crystals. Last not least, the efficiency of mechano-electrical energy conversion the PEM (TK-co-PEGDA/HMITFSI) is discussed. Chapter V addresses the mutual solubility of ionic liquid (IL) (open full item for complete abstract)

Committee: Thein Kyu (Advisor); Xing Gong (Committee Member); Kevin Cavicchi (Committee Member) Subjects: Energy; Engineering; Polymer Chemistry; Polymers

Doctor of Philosophy, University of Akron, 2018, Polymer Engineering

Present dissertation outlines a study of the basic important physicochemical properties of photo-cured polymer electrolyte membranes (PEM) that can be enhanced and optimized in order to be implemented as electrolyte in solid-state Li-ion batteries. The studied properties include mechanical integrity, ionic conductivity, thermal and electrochemical stability, etc. This dissertation also introduces and characterizes a novel application of PEMs as energy harvesting materials, due to their capability to transform mechanical stimuli into an electrical signal and vice versa. Chapter I provides a brief overview of the general content of the dissertation. Chapter II presents the material that was taken as the basis for the study. It contains essential information related to the battery principles, operation, development and applications. In addition, it encompasses the description of electroactive polymers, which are in principle, equivalent to the discovered flexoelectric PEMs that are as well introduced in this work. Chapter III illustrates the materials, methods and calculations utilized to perform and analyze the data collected for the purpose of the study. Chapter IV describes an incorporation of mercaptopropyl methyl siloxane homopolymer (thiosiloxane) as a co-component to the matrix of the PEM, which in result enables enhancement of the polymer segmental motion and hence, the ionic conductivity. UV irradiation was applied to various thiosiloxane and poly(ethylene glycol) diacrylate (PEGDA) mixtures to get the `thio-ene' reaction between the thiol functionality and the double bonds of the PEGDA precursor, which formed a complete amorphous self-standing PEM. The thiosiloxane modified PEM film exhibits higher extension-at-break in comparison to the PEM containing only PEGDA such as PEGDA700/SCN/LiTFSI 20/40/40, FTIR and Raman spectroscopy techniques were employed to detect the thiol (SH) groups consumed after performing the so-called thiol-ene reaction. It was fou (open full item for complete abstract)

Committee: Thein Kyu Dr (Advisor); Mark Soucek Dr (Committee Member); Younjin Min Dr (Committee Chair); Steven Chuang Dr (Committee Member); Siamak Farhad Dr (Committee Member) Subjects: Chemistry; Energy; Plastics; Polymer Chemistry; Polymers; Solid State Physics

Master of Sciences (Engineering), Case Western Reserve University, 2018, EMC - Mechanical Engineering

Poly(ethylene oxide)-LiTf-Al2O3 and Poly(ethylene oxide)-LiTf-Li1.5 Al0.5Ge1.5(PO4)3 composite solid electrolyte films for use in Lithium ion batteries were fabricated by aerosol jet deposition. The composite electrolytes were synthesized using three distinctly sized Al2O3 nanoparticles with specific surface areas of 111, 9.08 and 6.02 m2/g respectively, while the LAGP particles had a specific surface area of 7.25 m2/g. Each composite electrolyte was synthesized with EO:Li equal to 16:1, while the volume proportion of added ceramic was varied from 0 to 18% in relation to the PEO-based polymer matrix. In general, electrolyte films containing particles with high surface area and loaded at low volume fractions had greater conductivities. For example, composite electrolytes containing Al2O3 (111 m2/g) at a proportion of 3.5 vol.% showed the highest ionic conductivity of 3.99×10-5 Scm-1 at 30oC. Electrolytes containing LAGP particles generally performed better than films containing comparable sized Al2O3, such as the electrolyte containing LAGP (7.25 m2/g) at a proportion of 3.5 vol.% which obtained the second highest ionic conductivity of 2.24×10-5 Scm-1 at 30oC. Both electrolytes showed ionic conductivities approximately two orders of magnitude higher than the PEO-based electrolyte with no ceramic filler.

Committee: Vikas Prakash Dr. (Committee Chair); Thomas Howell Dr. (Advisor); Dan Lacks Dr. (Committee Member); Clare Rimnac Dr. (Committee Member) Subjects: Chemical Engineering; Electrical Engineering; Energy; Materials Science; Mechanical Engineering; Polymer Chemistry; Polymers

Master of Science in Polymer Engineering, University of Akron, 2017, Polymer Engineering

Based on the ternary phase diagram of polyethylene (glycol) diacrylate (PEGDA), ethylene carbonate (EC) and lithium bis-(trifluoromethane sulfonyl) imide (LiTFSI), polymer electrolyte membranes (PEMs) were fabricated in various proportions via photo-polymerization. Ionic conductivities of PEMs containing various ratios of three constitutes were measured by means of AC Impedance spectroscopy. Solid polymer electrolyte membrane, consisting of 20/40/40 PEGDA/EC/LiTFSI, was chosen as the appropriate solid PEM that afforded high ionic conductivity and good mechanical properties. The ionic conductivity of such PEM at 25 °C was found to reach a superionic level of 10-3 S cm-1, which is rather difficult to come by for a conventional solid-state electrolyte. More importantly, the present PEM was compatible with conventional electrodes such as LiFePO4 (LFP), Li4Ti5O12 (LTO) and graphite. The Li/PEM/LTO cell was found to achieve the capacity value of 180 mAh/g at a current rate of 0.2 C for both room temperature and 60 °C, which was even higher than the theoretical capacity of LTO of 170 mAh/g. What is more, the capacity of Li/PEM/LTO cell at 2 C, which was rather a high speed for a solid electrolyte membrane, could reach 140 mAh/g, indicating that the PEM was truly compatible with LTO electrode at both high cycling speed and high temperature. In addition, the LTO half-cell was found to survive charge/discharge cycling for more than 200 cycles with 95% retention, which implied that little or no degradation of the electrode occurred during the charge/discharge cycling. The Li/PEM/LFP half-cell and Li/PEM/graphite half-cell also reached the capacity close to the theoretical value. The high thermal and chemical stability of PEM confirmed that the present solid PEM could be a great alternative to the liquid electrolyte having advantages of non-flammable, solvent free, flexible, light weight, low cost and easy processing.

Committee: Thein Kyu (Advisor); Xiong Gong (Committee Member); Zhenmeng Peng (Committee Member) Subjects: Polymer Chemistry; Polymers

Master of Science in Polymer Engineering, University of Akron, 2017, Polymer Engineering

Ionic liquids (ILs) and polymeric ionic liquids (PILs) have stirred great interests in chemical and material science because of their outstanding characteristics such as nearly nonvolatile, high ionic conductivity, thermal and chemical stability, easy to handle. One of the major driving forces behind their study is their great potential serving as the substitute for traditional organic solvents and electrolytes. Glass formation behavior has great impact on the ion conductivity and mechanical properties of ILs and PILs. A better understanding the relationship between glass formation behavior, ion conductivity, chemistry, and mechanical properties would facilitate the design of ion containing materials with high ionic conductivity as well as improved mechanical properties. In this work, molecular simulation has been employed to study imidazolium based ILs and their corresponding PILs. In particularly, the Predictive Stepwise Quenching (PreSQ) protocol is used to measure the segmental relaxation time and predictive glass transition temperature. After polymerization, PILs have higher glass transition temperature as well as higher decoupling of ionic conductivity from structural dynamics, compared to ILs. Glass transition temperature and fragility seem to not correlate with decoupling, which is in agreement with experiments data. However, our results suggest that decoupling of ion conductivity from segmental relaxation time are strong correlated with Debye Waller factor, molecular volume and activation energy. High molecular volume not only renders low glass transition temperature, but also gives low decoupling for PILs. This finding improves the fundamental understanding of ILs and PILs and provides a guideline for the design of ion containing materials.

Committee: David Simmons Dr. (Advisor) Subjects: Physics; Polymers

Doctor of Philosophy, University of Akron, 2016, Polymer Engineering

In pursuit of safer and more flexible solid-state lithium ion batteries, solid polymer electrolytes have emerged as a promising candidate. The present dissertation entails exploration of solid plasticized, photopolymerized (i.e. ultraviolent-cured) polymer electrolyte membranes (PEM) for fulfilling the critical requirements of electrolytes, such as high ionic conductivity and good thermal and electrochemical stability, among others. Electrochemical performance of PEMs containing lithium ion half-cells was also investigated at different two temperatures. Phase diagram approach was adopted to guide the fabrication of two types of plasticized PEMs. Prepolymer poly (ethylene glycol) diacrylate (PEGDA) was used as a matrix for building an ionic conductive and mechanically sturdy network. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was incorporated as a source of lithium ions, while a solid plasticizer succinonitrile (SCN) and a liquid plasticizer tetraethylene glycol dimethyl ether (TEGDME) were incorporated in the respective systems. The important role of plasticizer on the enhancement of ionic conductivity (σ) to the superionic conductive level (10-3 S/cm) was revealed in both systems. It is worth noting that photopolymerization induced crystallization (PIC) occurred during UV-curing in the SCN-rich region of the ternary PEGDA/LiTFSI/SCN ternary mixtures. The PEM thus formed contained a plastic crystal phase, which showed lower σ relative to their amorphous PEGDA/LiTFSI/TEGDME counterpart. Comparisons on other thermal and electrochemical properties of the two types of PEMs are presented in Chapter IV. For the PEGDA/LiTFSI/SCN PEMs, fundamental study was carried out to clarify the relationship between σ and glass transition temperature (Tg). In lithium salt/polymer binary PEMs, increase in Tg and reduction in σ were observed; these may be attributed to ion-dipole complexation between dissociated lithium cations and ether oxygen upon salt addition. Notably (open full item for complete abstract)

Committee: Thein Kyu (Advisor); Xiong Gong (Committee Member); Younjin Min (Committee Member); Jie Zheng (Committee Member); Yu Zhu (Committee Member) Subjects: Alternative Energy; Energy; Materials Science; Physical Chemistry; Polymers

Master of Science, University of Akron, 2014, Polymer Engineering

Binary and ternary phase diagram of poly(ethylene glycol) dimethacrylate (PEGDMA), bis(trifluoromethane)sulfonimide (LiTFSI), and succinonitrile (SCN) blends have been established by means of differential scanning calorimetry and polarized optical microscopy. The binary phase diagram of PEGDMA/SCN mixture is of typical eutectic type, whereas the binary phase diagram of PEGDMA/LiTFSI mixture exhibits a wide single-phase region at the intermediate compositions. The ternary phase diagram of PEGDMA/SCN/LiTFSI mixture shows a wide isotropic region. The polymer electrolyte membrane (PEM), which is formed by ternary blends in this region after UV-crosslinking, remains in the isotropic phase and performs. The room temperature ion conductivity as evidenced in AC impedance measurement, was found to be extremely high (i.e., 10-3 S/cm). This ionic conductivity increases to 10-2 S/cm at 60 °C that continues to improve further up to 135 °C investigated. More importantly, the high ionic conductivity behavior is reproducible in repeated heating/cooling cycles. Those PEM are solid-state, stretchable, nonflammable, and light weight, which may be applicable to lithium ion battery as a replacement of commercial liquid electrolyte. SCN in ternary blends affords not only dissociation of the lithium salt, but also plasticization to the cross-linked PEGDMA network. Last not least, thermal and electrochemical stability of these membranes were examined for further application probability.

Committee: Thein Kyu Dr. (Advisor); Nicole Zacharia Dr. (Committee Member); Xiong Gong Dr. (Committee Member) Subjects: Energy; Engineering; Polymer Chemistry; Polymers

Master of Science (MS), Wright State University, 2008, Chemistry

Ionic liquids are an attractive possibility for battery electrolytes. Five ionic liquids were synthesized using a 1-alkyl-3-methylimidazolium (XMI+) cation, where the alkyl group was ethyl, propyl, butyl, pentyl, or hexyl, and a bis(pentafluoroethyl-sulfonyl)imide (Beti-) anion. The absorption and desorption of water, conductivities, densities, viscosities, decomposition temperatures, and electrochemical properties were studied. These ionic liquids were found to absorb less water than previously studied ionic liquids with tetrafluoroborate (BF4-) and hexafluorophosphate (PF6-) anions. Their conductivities decreased with longer alkyl chains on the imidazolium cation and were lower than ionic liquids with BF4- as the anion. The densities of the ionic liquids decreased with increasing temperature and alkyl chain length. Viscosities decreased with increasing temperature but increased with increasing chain length. All of the ionic liquids were found to be thermally stable to nearly 400 °C. The potential windows increased with increasing chain length, from 4.2 V (EMIBeti) to 4.7 V (HMIBeti).

Committee: Vladimir Katovic PhD (Committee Chair); William Feld PhD (Committee Member); David Grossie PhD (Committee Member) Subjects: Chemistry

Master of Science (MS), Ohio University, 2012, Electrical Engineering (Engineering and Technology)

Curcumin is a versatile chemical. It is used in food, medicine and electrical engineering. Use of curcumin in medical fields has been concentrated on the treatment of cancer, but it is a traditional spice that has been used in food preparation for millennia. Curcumin has seldom been used in physics, and electronics. In fact, curcumin gained its importance for its under representing ligand suitable for holding metal ions suspended in an insulating matrix of organic polymer. It consists of two regions: The ¿¿¿¿--diketone moiety for holding the metal, and the phenol group for attaching to the organic polymer. Its electronics applications have been focused primarily on the conversion of light to electricity. The unmodified structure of curcumin is not stable enough for photoluminescence because of its severe absorption in 340 nm - 535 nm wavelength range. Surprisingly, modified curcumin structures proved to be photo stabile in the visible range of 420 nm - 580 nm. Recently it was reported that 0.6% efficient photovoltaic material can be achieved using curcumin. In addition, curcumin dyes are chemically stable and eco-friendly. The project began with Dr. Butcher's, Department of Chemistry, Ohio University, suggestion that curcumin might serve as a means for making electrically conducting polymers. Initial work conducted by this research led to the investigation of photovoltaic properties of engineered curcuminated epoxy and ITO glass as a transparent electrode. No photovoltaic behavior was observed, but the changes in resistance noted that were sufficiently interesting to warrant detailed investigation. In the project, we used purified curcumin to prepare a novel copper doped curcuminated epoxy polymer and studied electrical properties at ambient temperature. The Design of Experiments method was applied to this study for the purpose of determining the significance of various constituents on the conductivity. Sixteen compositions were prepared and investigated using a Kei (open full item for complete abstract)

Committee: Jadwisienczak Wojciech PhD (Advisor); Savas Kaya Savas (Committee Member); Butcher Jared (Other); Whaley Ralph (Committee Member) Subjects: Engineering

Doctor of Philosophy, University of Akron, 2012, Polymer Engineering

The ultimate goal of this work is to fabricate self-standing polymer lithium electrolytes and flexible reflective liquid crystal displays by first understanding the equilibrium phase behavior of their constituent mixtures. The isotropic phase facilitates processing and allows better control of the final morphology. It is anticipated that ionic conductivity in polymer lithium electrolytes is favored with isotropic morphology which means that initial amorphous structure should be preserved in the final self-standing membranes. On the other hand, phase separation induced by polymerization is a necessary condition to generate cholesteric liquid crystal dispersions. To understand the effect of morphology on the ionic conductivity, a ternary phase diagram of polyethylene oxide (PEO), succinonitrile (SCN) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was established. Ionic conductivity was found to improve in the isotropic region containing high concentrations of SCN. Later, polyethylene glycol diacrylate (PEGDA) having a lower molecular weight of 700 g/mol was used in lieu of PEO and a room temperature ternary phase diagram of PEGDA/SCN/LiTFSI was constructed. Isotropic membranes with ionic conductivities between 10-5 S/cm to 10-3 S/cm at room temperature were achieved. Furthermore, membranes fabricated with PEGDA having a molecular weight of 6000 g/mol, SCN and LiTFSI have a higher ionic conductivity of 2.9*10-3 S/cm at room temperature and increase to 10-2 S/cm at 60 C. This material also exhibits stronger tensile strength and modulus that can be further improved with the addition of trimethylolpropane triacrylate (TMPTA) crosslinker. The fabrication of polymer dispersed cholesteric liquid crystals (CLC) was carried out by first studying the phase behavior of EMA/TMPTA/CLC mixtures. Ternary phase diagram of EMA, TMPTA and CLC was constructed in order to identify the isotropic region necessary to select an appropriate precursor mixture. Reflectivity and electr (open full item for complete abstract)

Committee: Thein Kyu Dr. (Advisor); Homero Castaneda Dr. (Committee Member); Robert Weiss Dr. (Committee Chair); Steven Chuang Dr. (Committee Member); Xiong Gong Dr. (Committee Member) Subjects: Polymers

Doctor of Philosophy, University of Akron, 2007, Polymer Engineering

Novel flexible solid polymer electrolytes with both high ionic conductivity and good dimensional stability based on thermoplastic polyurethane (TPU)/polyether-modified polysiloxane (PEMPS) electrolytes with various lithium salts were developed. The salts used include lithium chloride (LiCl), lithium perchlorate (LiClO4), lithium bistrifluoromethanesulfonimidate (LiN(SO2CF3)2 [LITFSI] ). These polymer electrolytes were prepared by a solvent-free, in-situ process, instead of the conventional solution casting method. In this process, the monomer, polytetramethylene glycol (PTMG), was the solvent for dissolving lithium salts instead of a highly volatile one. This process included two steps: (a) dissolve lithium salts in PTMG and PEMPS; and (b) add 4,4'-diphenylmethane diisocyanate (MDI), 1,4 butane diol (BDO) to start polymerization of polyurethane. The dissolution of salts in PTMG and PEMPS, the interaction of salt with PTMG and PEMPS, and the miscibility of PTMG/PEMPS were characterized using differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), and optical microscopy. The structure of the anion greatly affected the solubility of salts in PTMG and PEMPS. Salts with large anions, such as ClO4- and TFSI-, exhibited better solubility than ones with small anions, such as Cl-. Salts enhanced the compatibility between PEMPS and PTMG. Kinetics studies of polyurethane polymerization using the isothermal calorimetry indicated that the lithium salt slightly retarded the polymerization of TPU due to interaction of lithium ions with hydroxyl groups. Thermogravimetric analysis (TGA) characterization and tensile testing of TPU/PEMPS electrolytes demonstrated good thermal and dimensional stability. Morphological studies of TPU and TPU/PEMPS electrolytes were conducted using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). TPU/PEMPS electrolytes exhibit a multiphase morphology with PEMPS dispersed in the TPU (open full item for complete abstract)

Committee: Kyonsuku Min (Advisor) Subjects:

Doctor of Philosophy in Clinical-Bioanalytical Chemistry, Cleveland State University, 2012, College of Sciences and Health Professions

Morphological and thermodynamic transitions in drugs as well as their amorphous and crystalline content in the solid state have been distinguished by Thermal Analytical techniques, which include dielectric analysis (DEA), differential scanning calorimetry (DSC), and macro-photo-micrography. These techniques were used to establish a structure vs. property relationship with the United States Pharmacopeia (USP) standard set of active pharmaceutical ingredients (API). DEA measures and differentiates the crystalline solid (low; 10¿¿¿¿¿ pS/cm) and amorphous liquid (high; 10¿¿¿ pS/cm) API electrical ionic conductivity. DEA ionic conductivity cycle establishes the quantitative amorphous/ crystalline content in the solid state at frequencies of 0.1 - 1.00 Hz and to greater than 30 ¿¿C below the melting transition as the peak melting temperature. This describes the “activation energy method”. An Arrhenius plot, log ionic conductivity vs. reciprocal temperature (1/K), of the pre-melt DEA transition yields frequency dependent activation energy (Ea, J/mol) for the complex charging in the solid state. The amorphous content is inversely proportional to the Ea. Where, Ea for the crystalline form is higher and lower for the amorphous form with a standard deviation of ¿¿ 2%. An alternate technique has been established for the drugs of interest based on an obvious amorphous and crystalline state identified by macro-photomicrography and compared to the conductivity variations. This second “empirical method” correlates well with the “activation energy” method. A comparison of overall average amorphous content by the empirical method had a linear relationship with the activation energy method with a correlation coefficient of R¿¿ = 0.925. Additionally, new test protocols have been developed which describe the temperature and material characterization calibration of thermal analyzers with pharmaceuticals. These test protocols can be blended into a universal standard protocol for DSC, DEA (open full item for complete abstract)

Committee: Mekki Bayachou PhD (Committee Chair); Alan Riga PhD (Committee Co-Chair); John Turner PhD (Committee Member); Bin Su PhD (Committee Member); Tobili Sam-Yellowe PhD (Committee Member) Subjects: Analytical Chemistry