Coarse-Grained Models of Ionic Solutions
Författare
Summary, in Swedish
Popular Abstract in English
Typically, when we speak of ionic solutions we mean a salt (as solute) dissolved in some liquid (the solvent). In this thesis, we predominantly consider ionic solutions for which there is no solvent---room-temperature ionic liquids (RTILs).
It follows that these liquids have a large concentration of charged particles, a property that causes them to be effective electrolytes in capacitors. A capacitor works as a rechargeable battery, storing a net charge (an excess adsorption of positive or negative particles) onto the surface of an electrode when a voltage is applied, and releasing them when connected to a circuit, creating a current to power some electrical components. The nature of this adsorption (or the `electric double layer') is therefore of interest to us. Another appealing feature of RTILs is the ability to control their physical properties by changing their chemical structures. Synthesizing ionic liquids is expensive, and there are vast numbers of possible compounds so there is a necessity to describe these chemicals theoretically, to explain and predict their behaviour.
However, the old theories of electrolyte-electrode behaviour fail under these high concentrations. Computer simulations of RTILs with all-atom forcefields can be very time-consuming, so to save time and gain a broader understanding, we can use less detailed, `coarse-grained' models. These simple models also allow easy implementation into a classical density functional theory framework, an approximate semi-analytical theory capable of delivering results of comparable accuracy to simulation, but at a fraction of the time.
Typically, when we speak of ionic solutions we mean a salt (as solute) dissolved in some liquid (the solvent). In this thesis, we predominantly consider ionic solutions for which there is no solvent---room-temperature ionic liquids (RTILs).
It follows that these liquids have a large concentration of charged particles, a property that causes them to be effective electrolytes in capacitors. A capacitor works as a rechargeable battery, storing a net charge (an excess adsorption of positive or negative particles) onto the surface of an electrode when a voltage is applied, and releasing them when connected to a circuit, creating a current to power some electrical components. The nature of this adsorption (or the `electric double layer') is therefore of interest to us. Another appealing feature of RTILs is the ability to control their physical properties by changing their chemical structures. Synthesizing ionic liquids is expensive, and there are vast numbers of possible compounds so there is a necessity to describe these chemicals theoretically, to explain and predict their behaviour.
However, the old theories of electrolyte-electrode behaviour fail under these high concentrations. Computer simulations of RTILs with all-atom forcefields can be very time-consuming, so to save time and gain a broader understanding, we can use less detailed, `coarse-grained' models. These simple models also allow easy implementation into a classical density functional theory framework, an approximate semi-analytical theory capable of delivering results of comparable accuracy to simulation, but at a fraction of the time.
Publiceringsår
2015
Språk
Engelska
Dokumenttyp
Doktorsavhandling
Förlag
Division of Theoretical Chemistry, Department of Chemistry, Lund University
Ämne
- Theoretical Chemistry
Nyckelord
- Monte Carlo
- Classical Density Functional Theory
- Coarse-Grained Models
- Ionic Liquids
- Prewetting
- Capillary Condensation
- Electric Double Layer
- Differential Capacitance.
Status
Published
Handledare
ISBN/ISSN/Övrigt
- ISBN: 978-91-7422-390-3
Försvarsdatum
13 mars 2015
Försvarstid
10:30
Försvarsplats
Lecture Hall B
Opponent
- Gerhard Kahl (Univ.Prof.Dr.)