Physical Sciences and Mathematics Commons^™

A Study Of The Ability Of Surface Active Materials To Increase The Evaporation Rates Of Small, Freely Falling Water Drops, David Alan Sierawski

Masters Theses

"The evaporation rate at 30°C of water droplets partially covered by surface active materials (SAM) were determined. While two of the SAM were studied at a single dew point depression (ΔT_DP), seven others were examined over a range of ΔT_DP values. It was found, by comparison with pure water drops under identical conditions, that SAM increases the evaporation rate as compared to the rate of an uncontaminated drop. The lack of effect of the hydrophobic chain length and the possible effect of the hydrophilic group on this phenomenon are discussed. The explanation proposed is that at 30°C …

Desorption Of Phosphorus From Si (111) Surfaces, Cesar Michel Magnin

Masters Theses

"Auger electron spectroscopy and mass analysis are used as complementary methods in evaluating desorption kinetics. For phosphorus on silicon, the order of desorption and activation energies of desorption are determined from continuously monitored phosphorus Auger electron signals during heating. These measurements indicate that diatomic phosphorus dissociates when adsorbed onto clean silicon. Mass spectrometer flash desorption spectra show that at least four distinct surface bonds are associated with the desorption of phosphorus. The dominant desorbed species is diatomic phosphorus at high coverage (> 0. 1 monolayer) and atomic phosphorus at low coverage (< 0.07 monolayer)"--Abstract, page ii.

Adsorption Of Water On Gold, Jean-Marc Louis Deschanel

Masters Theses

"Water adsorption isotherms on gold films were measured with a quartz crystal microbalance. Two gold films were studied: a "dirty" gold film contaminated by approximately one monolayer of carbon, and a "clean" gold film prepared by evaporating gold from a heated tungsten wire under high vacuum.

Water was found to chemisorb on both films according to a Freundlich type adsorption isotherm. Isosteric heats of adsorption were computed from the isotherm data. On the "clean" gold surface the isosteric heat showed a logarithmic decrease with increasing water coverage. The highest measured value for the heat of adsorption was 35 kcal mole …