In-situ Cleaning at Model Fabric Interfaces

Is it really clean!? A fabric surface may appear visibly clean when all but a few nm of soil have been removed. This is because the optical absorbance of most soils is insufficient to detect at monolayer levels, and spectroscopic techniques are easily misled by small 'lumps' of soil particles that cover only a small fraction of the surface, but have the equivalent volume to monolayer coverage. This is important because the residual soil may act as a hydrophobic seed layer to facilitate further soils and stain adhesion in the wash. We seek to quantify the fractional coverage of thin residual layers of soil components on model fabric surfaces. In these experiments, sub-micron layers of complex organic soil components will be deposited onto model fabric surfaces. Using a flow-cell setup, the extent of removal of these soils will be studied using NR under successively increasing surfactant concentrations.