In this work, ionic liquids (ILs) were investigated for use as battery electrolytes. The ILs were synthesized from quaternary ammonium and phosphonium salts and TFSI-. A dendrite free lithium metal anode was demonstrated by deposition of a lithium-potassium alloy. Several phosphonium ILs were synthesized using the TFSI- and PF6- anions until a room temperature IL was obtained. The smaller size, highly symmetric PF6- anion yielded high melting point salts, while TFSI- yielded much lower melting point ILs. When a room temperature IL, Bu3HexP+TFSI-, was obtained the analogous ammonium IL, Bu3HexP+TFSI-, was synthesized and compared. The phosphonium-based ionic liquid showed improved stability and physical properties compared to the analogous ammonium-based IL. The phosphonium-based IL had higher conductivity, 0.43 mS/cm, than the ammonium-based IL, 0.28 mS/cm. The addition of LiTFSI to both ILs led to a decrease in conductivity and increase in viscosity. The lower viscosity and higher stability of the phosphonium-based IL led to higher current density and stability for electrodeposited lithium metal. IL reduction interfered with lithium deposition reflecting lower coulombic efficiencies and giving the appearance of an unstable lithium couple. An optimum deposition potential was found which was bounded by the electrochemical stability of each IL. The stability of lithium in the ILs increased at lower temperature due to slower reactivity with the IL. Addition of higher quantities of lithium ions caused a higher fraction of the cathodic current going to lithium deposition that was reoxidized. The stability of lithium in the ILs increased at lower temperature due to slower reactivity with the IL. The electrodeposition and reoxidation of potassium was also demonstrated. Deposition of a lithium-potassium alloy caused slight increases in the cathodic and anodic currents along with higher coulombic efficiencies. Also, it was found that a lithium-potassium alloy could be deposited at high current for long times without the occurrence of dendrites.

The synthesis method for PEG/alkyl-based imidazolium/pyridinium ionic liquids was studied. Four steps were used to fabricate the membranes: polymerization, chloromethylation, linkage of the polymers with the pendent groups and membrane cast. Permeabilities and CO2/N2 selectivity of two membranes were examined and each showed remarkable CO2/N2 selectivity. CO2 permeability of the [PSM-MIM][Cl] membrane is better than that of the [PSM-MEIM][Cl] membrane, which is due to the steric hindrance of the methoxyethyl group. The syntheses of PEG/alkyl-based imidazolium/pyridinium ionic liquids (IL) were studied. PEG-based ILs were demonstrated to have better H2S solubilities than the alkyl-based ILs. H2S solubilities of the imidazolium ILs and pyridinium ILs were compared. The anion effects on H2S solubilities have been investigated, while the temperature effects on H2S solubilities will need to be studied in the near future.

xvii, 159 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Experimental studies on mix-conducting hetero-ionic junctions of anionically (PA A ) and cationically (PA C ) functionalized polyacetylene ionomers, as well as each individual ionomer, in thin-film sandwich configurations are reported for the purpose of better understanding the interaction between ionic and electronic charge transports in mixed ionic-electronic conductor (MIEC) systems. The transport of ions in both individual ionomers as well as their hetero-ionic junction was investigated via small-amplitude AC impedance spectroscopy in the absence of significant interference from the electronic charge transport. Modeling of the impedance results reveal important information about the materials such as: ion conductivity, activation energy of ion conduction, ion hopping frequency, dielectric constant, interfacial capacitance, and estimates of effective ion density. Electrochemical injection of electronic charge carriers into PA A and PA C from gold electrodes was monitored to determine the applied potentials needed to drive hole and electron injection into each ionomer. It is found that for both ionomers, the onset voltages for unipolar and bipolar charge injection are similar, and holes can be injected at close to zero bias. The responses of the complete Au|PA A |PA C |Au hetero-ionic junction, as well as each constituent ionomer layer in Au|Ionomer|Au configuration, to various stepping biases were investigated through current-voltage and impedance measurements to study the origin of the asymmetric current-voltage response observed in the hetero-ionic junction. Analysis of the results reveal a working mechanism of a mix-conducting junction that is fundamentally different from that of a purely electronic pn junction. When illuminated with light, the Au|PA A |PA C |Au junction exhibits unidirectional photovoltage and photocurrent with the PA A side at higher potential, while the Au|PA A |Au and Au|PA C |Au samples exhibit symmetric photoresponses. The efficiency of photocurrent generation in the Au|PA A |PA C |Au junction was found to be strongly dependent on the direction of illumination and on the sample thickness. These observations can be explained by the difference in the mobility of holes and electrons and the existence of a built-in ionic space charge region at the PA A |PA C interface. A mechanism of photoresponse unique to MIEC junctions was proposed, and the magnitude of built-in potential was estimated. / Committee in charge: J David Cohen, Chairperson, Physics; Mark Lonergan, Advisor, Chemistry; Roger Haydock, Member, Physics; David Strom, Member, Physics; David Tyler, Outside Member, Chemistry

abstract: The field of Ionic Liquid (IL) research has received considerable attention during the past decade. Unique physicochemical properties of these low melting salts have made them very promising for applications in a many areas of science and technology such as electrolyte research, green chemistry and electrodeposition. One of the most important parameters dictating their physicochemical behavior is the basicity of their anion. Using four sets of Protic Ionic Liquids (PILs) and spectroscopic characterization of them, a qualitative order for anion basicity of ILs is obtained. Protic Ionic Liquids are made by proton transfer form a Brønsted acid to a base. The extent of this transfer is determined by the free energy change of the proton transfer process. For the cases with large enough free energy change during the process, the result is a fully ionic material whereas if the proton transfer is not complete, a mixture of ions, neutral molecules and aggregates is resulted. NMR and IR spectroscopies along with electrochemical and mechanical characterization of four sets of PILs are used to study the degree of ionicity. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2016

Orientador: David Mendez Soares / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-15T00:08:17Z (GMT). No. of bitstreams: 1 Gomes_WyllersonEvaristo1983-_M.pdf: 20027750 bytes, checksum: ac9756c2723f3eb80a562d792355af61 (MD5) Previous issue date: 2010 / Resumo: As propriedades dinâmicas e estruturais de filmes de surfatantes adsorvidos em superfícies são de interesse fundamental e aplicado. Investigamos a formação de estruturas auto-organizadas de surfatantes sobre superfícies de substrato sólido de ouro. Estudamos sua dinâmica de formação e estabilidade. As estruturas foram feitas em ambiente aquoso, sob condições físico-químicas controladas. Tais estruturas são potenciais candidatas a modelos in vitro de membrana biológica (sistema biomimético) / Abstract: The structural and dynamical properties of surfactant films are both of fundamental and applied interest. To understand the formation mechanism of these structures we have studied the formation of surfactant self-assembled aggregates on gold surfaces. Their dynamic and stability were investigated. All experiments were performed in aqueous media, under specific physical and chemical conditions. These structures are potential candidates of in vitro models for biological membranes (bio-mimetic systems) / Mestrado / Físico-Química / Mestre em Física

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Ce travail traite du rôle joué par les fonctions de surface sur le transport et le piégeage de cations alcalins en présence d'eau, dans des SBA-15 fonctionnalisées. Il s'agit aussi d'étudier les effets de confinement sur la thermodynamique de l'eau adsorbée. La première étape a consisté à synthétiser les différentes SBA-15, contenant des groupements fonctionnels acides du type PO(OH)2, SO3H, COOH ainsi que leurs équivalents alcalins contenant du Li, Na, K ou Rb. Les solides obtenus ont été caractérisés à l'état sec par DRX, adsorption-désorption de N2 et par RMN du solide, afin de rendre compte respectivement de l'organisation du réseau poreux, des caractéristiques texturales et de la structure locale des motifs organiques. Puis, nous avons étudié ces solides en présence d'eau adsorbée. Nous avons mis en évidence l'instabilité des solides alcalins contenant des ions Na+, K+ et Rb+. Nous proposons également une étude thermodynamique de la fusion de l'eau confinée par DSC, pour laquelle nous montrons que déplacement de la température de transition solide/liquide de l'eau adsorbée dépend de la taille des pores. Ensuite, nous avons analysé les dynamiques ionique et moléculaire de l'eau confinée par Spectroscopie d'Impédance Complexe (SIC) et par diffusion quasi-élastique des neutrons (QENS). L'étude par SIC nous a permis, pour les solides acides, de révéler une conduction protonique selon un mécanisme de Grötthus, et de montrer une dépendance entre les valeurs de conductivité et le pKa des fonctions acides. Finalement par QENS, nous avons observé deux régimes de mobilité des protons, de part et d'autre de 220K, que nous avons associés à des populations différentes de protons. / This work deals with the role played by the functions of surface transport and trapping of alkali cations in the presence of water in SBA-15 functionalized. It is also to study the effects of confinement on the thermodynamics of the adsorbed water. The first step was to synthesize the different SBA-15 containing acidic functional groups of type PO (OH) 2, SO3H, COOH and alkali equivalents containing Li, Na, K or Rb. The solids obtained were characterized in the dry state by XRD, N2 adsorption-desorption and solid state NMR, respectively, to reflect the organization of the pore network, and textural characteristics of the local structure of organic patterns. Then, we studied the solid presence of adsorbed water. We have highlighted the instability of solids containing alkali ions Na +, K + and Rb +. We also study the thermodynamics of melting of water confined by DSC, for which we show that displacement of the transition temperature of solid / liquid water adsorbed depends on the pore size. Then, we analyzed the ionic and molecular dynamics of water confined by Complex Impedance Spectroscopy (CIS) and by quasi-elastic neutron scattering (QENS). The CIS study allowed us, for strong acids, reveal a proton conduction mechanism in a Grotthus, and show a dependence between conductivity values and the pKa of the acid functions. Finally by QENS, we have observed two regimes of mobility of protons, on both sides of 220K, which we associated with different populations of protons.

An expression for the dielectric susceptibility tensor of a cubic ionic crystal has been derived using the classical Liouville operator. The effect of cubic anharmonic forces is included as a perturbation on the harmonic crystal solution, and a series expansion for the dielectric susceptibility is developed. The most important terms in the series are identified and summed, yielding an expression for the complex susceptibility with an anharmonic contribution which is linearly dependent on temperature. A numerical example shows that both the real and imaginary parts of the susceptibility are continuous, finite functions of frequency.

京都大学 / 0048 / 新制・論文博士 / 博士(理学) / 乙第12997号 / 論理博第1553号 / 新制||理||1604(附属図書館) / 32925 / (主査)教授 北川 宏, 教授 竹腰 清乃理, 教授 有賀 哲也 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DGAM

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