A mathematical model is developed to describe the micro/nano-scale fluid flow and heat/mass transfer phenomena in an evaporating extended meniscus, focusing on the transition film region under nonisothermal interfacial conditions. The model incorporates thermocapillary stresses at the liquid-vapor interface, a slip boundary condition on the solid wall, polarity contributions to the working fluid field, and binary mixture evaporation. The analytical results show that the adsorbed film thickness and the thin film length decrease with increasing superheat by the thermocapillary stresses, which influences detrimentally the evaporation process by degrading the wettability of the evaporating liquid film. In contrast, the slip effect and the binary mixture enhance the stability of thin film evaporation. The slip effect at the wall makes the liquid in the transition region flow with smaller flow resistance and thus the length of the transition region increases. In addition, the total evaporative heat flow rate increases due to the slip boundary condition. The mixture of pentane and decane increases the length of the thin film by counteracting the thermocapillary stress, which enhances the stability of the thin film evaporation. The polarity effect of water significantly elongates the thin film length due to the strong adhesion force of intermolecular interaction. The strong interaction force restrains the liquid from evaporation for a polar liquid compared to a non-polar liquid. In the experimental part, laser induced fluorescence (LIF) thermometry has been used to measure the microscale temperature field of a heated capillary tube with a 1 mm by 1 mm square cross section. For the temperature measurement, the calibration curve between the temperature and the fluorescent intensity ratio of Rhodamine-B and Rhodamine-110 has been successfully obtained. The fluorescent intensity ratio provides microscale spatial resolution and good temperature dependency without any possible bias error caused by illuminating light and background noise usually encountered in conventional LIF techniques. For the validation of the calibration curve obtained, thermally stratified fields established inside a glass cuvette of 10 mm width were measured. The measurement result showed a good agreement with the linear prediction. The temperature measurement in a 1 mm capillary tube could provide the feasible method of temperature measurement for the thin film region in the future.

In the past decade, electrostatic layer-by-layer (LBL) assembly has gained attention because it is a facile and robust method to prepare thin polymer films. Due to the industrial importance and natural abundance of cellulose, its incorporation into LBL films is of particular interest. This thesis examines the use of nanocrystalline cellulose, prepared by sulfuric acid hydrolysis of cotton, in polyelectrolyte multilayer films. Conventional solution-dipping and a spin-coating variant of LBL assembly both resulted in chemically defined, reproducible, and smooth films with adjustable properties. Surface morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and film growth was monitored by X-ray photoelectron spectroscopy (XPS) and optical techniques. Orientation of the rod-like cellulose nanocrystals imparted anisotropic film properties, and birefringence was calculated from angle dependent and wavelength dependent optical reflectometry measurements. While spin-coating resulted in radial orientation of the nanocrystals, electrostatic adsorption in a magnetic field led to linear alignment. The internal structure, surface orientation and wettability of these materials were investigated. The attractive and repulsive forces acting close to the surface of the multilayer films in aqueous media were measured by colloid-probe AFM and the interaction forces between the film surfaces and charged colloidal-probes were compared to the predictions of the DLVO theory. The applications and advantages of polyelectrolyte multilayers containing nanocrystalline cellulose and their potential as model cellulose surfaces are discussed.

This thesis investigates the application of low energy electron irradiation to 1,3,5-trimethylbenzene films to test whether site-selective C–H bond cleavage can be achieved in a molecule presenting both aliphatic and aromatic target sites. IRRAS was used to characterize the orientation of vapour-deposited 1,3,5-trimethylbenzene on Au(111) and alkanethiolated gold under UHV and cryogenic conditions. On both substrates, the disordered as-deposited films were transformed by thermal treatment, producing two film structures – within the first 4-monolayers, aromatic rings lie nearly parallel to the metal surface, while molecules in additional layers are more upright. Low energy electron irradiation (0-10 eV) produced no dissociations in 1,3,5-trimethylbenzene; however, low energy electron transmission spectra indicate charge accumulates at interstitial sites in the mesitylene film, decelerating subsequent incident electrons. These decelerated electrons traverse the charged film and are reaccelerated, inducing dissociations in the underlying SAM. Contrary to literature claims, 1,3,5-trimethylbezene is a poor molecule for adsorption studies such as BET as the initial adsorption is disordered and thermodynamically unstable.

Previous studies have attempted to probe the structure of ultra-thin Nickel silicide films as they evolve in the manufacturing process with limited success. These studies have used ultra-thin Nickel silicide films that were quenched during the manufacturer's annealing process at select temperatures. This study aims to determine the structure of quenched ultra-thin Ni-Si films using Grazing Incidence X-Ray Absorption Near Edge Spectroscopy (GI-XANES) and ab-initio calculations (FDMNES). Successful calculations were prepared for the δ and θ Ni2Si phases, as well as the Ni3Si2, NiSi and NiSi2 phases. The GI-XANES experimental data was taken at the Canadian Light Source, at the Hard X-Ray Microanalysis Beamline (HXMA). XANES and FDMNES are used to identify two phases of the ultra-thin films: the as-deposited phase as a low-ordered Ni3Si2 phase, and the epitaxial NiSi2 phase was found in samples annealed past 400˚C.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.