| When a liquid is placed on a surface it will either spread evenly to form a at film with zero contact angle or it will form a drop with a finite contact angle with the surface. These two situations are referred to as wet and partially wet respectively. At temperatures and pressures dictated by the properties of the two materials, a phase transition can occur between partially wet and wet. This transition, which is known as a wetting transition, has never been observed for water. This work concerns the development of a high temperature, high pressure experimental apparatus to detect a wetting transition of water.;The construction of an experimental cell which can withstand pressures to 217 atmospheres and temperatures to 374° C with optical windows presents a significant experimental challenge. Three high pressure cells with optical widows were constructed during the course of this project which had varying degrees of success. The evolution and engineering improvements of these cells from the Mark I to the Mark III is described. Simulations are presented to show the feasibility of using interferometry as a wetting transition detection method. Error analysis data for the third design, Mark III cell, demonstrates the viability of this apparatus for detection of a wetting transition. |
