Chiral structure formation is ubiquitous in surface self-assembly. Molecules that do not undergo chiral recognition in solution or fluid phases can do so when their configurational freedom is restricted in the two-dimensional field of a substrate. The process holds promise in the manufacture of functional materials for chiral catalysis, sensing or nonlinear optics. In this thesis, we investigate the influence of surface attraction and geometry on adsorption-induced chiral separation in several model molecules, as well as the relationships between molecular features, specifically molecular geometry and charge distribution, and chiral recognition at surface self-assembly. Simple model molecules embody the fundamental interactions involved in supramolecular structure formation in experimental systems, and allow the in-depth investigation of key parameters. Chiral pattern formation at the surface self-assembly is a complex problem, even in cases where very small organic molecules are considered. Even though the adsorption behaviour of small organic molecules on gold surfaces has been investigated extensively so far experimentally and theoretically, much of their chiral behaviour is yet to be understood at a molecular level. Theoretical investigations of chiral self-assembly of sulfur containing amino acids onto achiral and chiral gold surfaces is also presented in this thesis. By understanding chiral self-assembly on solid surfaces, one may control and direct it towards creating materials with desired functionality. / Graduate / 0494 / tp.popa@gmail.com

The objective of this thesis was to further develop a methodology for surface tension measurement called Axisymmetric Drop Shape Analysisn(ADSA) and to adapt it to studies of lung surfactants, i.e. the material that coats and facilitates the functioning of the lungs of all mammals. The key property of a functioning lung surfactant is its surface tension, which can reach extremely low values. Such values are difficult to measure; but a certain configuration of ADSA, using a constrained sessile drop (ADSA--CSD), is capable of performing such measurements. Clinically, lung surfactant films can be altered from both sides, i.e. from the airspace as well as from the bulk liquid phase that carries the film. Therefore, being able to access the interface from both sides is important. Here, ADSA--CSD was redesigned to be used as a micro film balance allowing access to the interface from both gas- and liquid-side. This allows deposition from the gas side as well as complete exchange of the bulk liquid phase. The new design was used to study lung surfactant inhibition and inhibition reversal. A dynamic compression-relaxation model (CRM) was developed to describe the mechanical properties of lung surfactant films by investigating the response of surface tension to changes in surface area. The model evaluates the quality of lung surfactant preparations -- beyond the minimum surface tension value -- and calculates the film properties, i.e. elasticity, adsorption and relaxation, independent of the compression protocol. The accuracy of the surface tension measurement can depend on drop size. A detailed analysis of drop shapes and accuracy of measured surface tension values was performed using a shape parameter concept. Based on this analysis, the design of ADSA--CSD was optimized to facilitate more accurate measurements. The validity analysis was further extended to the more conventional pendant drop setup (ADSA--PD). An overall upgrade of both hardware and software of ADSA--CSD, together with extensive numerical work, is described and applied to facilitate a more efficient operation. Finally, it is noted that the ADSA--CSD setup developed here can be used for a wide range of colloid and surface chemical applications.

The objective of this thesis was to further develop a methodology for surface tension measurement called Axisymmetric Drop Shape Analysisn(ADSA) and to adapt it to studies of lung surfactants, i.e. the material that coats and facilitates the functioning of the lungs of all mammals. The key property of a functioning lung surfactant is its surface tension, which can reach extremely low values. Such values are difficult to measure; but a certain configuration of ADSA, using a constrained sessile drop (ADSA--CSD), is capable of performing such measurements. Clinically, lung surfactant films can be altered from both sides, i.e. from the airspace as well as from the bulk liquid phase that carries the film. Therefore, being able to access the interface from both sides is important. Here, ADSA--CSD was redesigned to be used as a micro film balance allowing access to the interface from both gas- and liquid-side. This allows deposition from the gas side as well as complete exchange of the bulk liquid phase. The new design was used to study lung surfactant inhibition and inhibition reversal. A dynamic compression-relaxation model (CRM) was developed to describe the mechanical properties of lung surfactant films by investigating the response of surface tension to changes in surface area. The model evaluates the quality of lung surfactant preparations -- beyond the minimum surface tension value -- and calculates the film properties, i.e. elasticity, adsorption and relaxation, independent of the compression protocol. The accuracy of the surface tension measurement can depend on drop size. A detailed analysis of drop shapes and accuracy of measured surface tension values was performed using a shape parameter concept. Based on this analysis, the design of ADSA--CSD was optimized to facilitate more accurate measurements. The validity analysis was further extended to the more conventional pendant drop setup (ADSA--PD). An overall upgrade of both hardware and software of ADSA--CSD, together with extensive numerical work, is described and applied to facilitate a more efficient operation. Finally, it is noted that the ADSA--CSD setup developed here can be used for a wide range of colloid and surface chemical applications.

The surface force apparatus (SFA) has been an important technique for making direct force measurements and has contributed enormously to our understanding of colloidal interactions. The conventional SFA has been limited to measuring forces between solid surfaces, until recently when a modified SFA was developed at the Ian Wark Research Institute [1]. A fluid drop (mercury) is introduced into the apparatus which allows a range of deformable surfaces to be studied in the SFA. This project is an extension of this technique. Interactions between a mica sheet and a mercury drop are studied, including the modification of mercury with self-assembled monolayers (SAMs) of thiol surfactants, and the drop deformation due to non-equilibrium adsorption effects and hydrodynamic forces.

Thesis (M.Eng.). / Written for the Dept. of Electrical and Computer Engineering. Title from title page of PDF (viewed 2008/04/12). Includes bibliographical references.

Thesis (Ph. D.)--University of California, San Diego, 1998. / Vita. Includes bibliographical references (p. 235-244).

Thesis (doctoral)--Lund University, 1992. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 170-176). Available also in a digital version from Dissertation Abstracts.

Thesis (doctoral)--Lund University, 1992. / Added t.p. with thesis statement inserted.