Transport of Water by Surfactant Spreading in Unsaturated Porous Media

暴露在潮湿中的颗粒材料通常在每个颗粒的表面涂上一层薄薄的水。在材料可以使用之前，通常需要去除这些水。水中可能含有对回收很重要的溶解物质。干燥和回收是繁琐和昂贵的操作。一项新的技术表明，在这种“不饱和”的多孔介质中，表面活性剂在空气-水界面上传播时，会拖走大量的水。这种水的运动基本上不需要外部能量输入。表面活性剂在移动的薄水膜中的有效性的标准不同于大块体系，并且不被理解。这项研究的目的是了解和优化表面活性剂铺展的水分传输。最终实验将使用实验室中提供的经典表面化学技术进行。这项工作将对界面上的水的性质以及薄膜的总体性质提供新的认识。它直接应用于无需机械夯实的建筑物地基的室温干燥或脱水稳定，以及无需昂贵的开挖的地下采矿和环境清理。

Particulate material which is exposed to moisture typically has the surface of each particle coated with a thin film of water. It is often necessary to remove this water before the material can be used. The water may contain dissolved substances which are important to recover. Drying and recovery are tedious and expensive operations. A new technique shows that surfactants spreading at the air-water interface in such "unsaturated" porous media drag a significant amount of water with them. This water movement occurs with essentially no external energy input. The criteria for surfactant effectiveness in moving thin water films are different from bulk systems, and are not understood. The objectives of this research are to understand and optimize water transport by surfactant spreading. Definitive experiments will be conducted using classical surface chemistry techniques available in the laboratory. The work will shed new light on the character of water at interfaces, and on thin film properties in general. It has direct applications to room temperature drying or de-watering stabilization of building foundations without mechanical tamping of the earth, and underground mining and environmental cleanup without expensive excavation.