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The detergency of fabrics is a complex process that depends in part on the physicochemical actions of the detergent solution and the mechanical actions exerted on the fabric. Experimental techniques have been devised for evaluating the soil removal ability of detergent in the washing of fabric (1, 2). However, most of these techniques require simultaneous actions of the detergents and the mechanical force. Thus, it is difficult with the techniques to analyze the essential role of detergent alone in the soil removal process. The detergency of a fiber assembly such as fabric may involve a dynamic equilibrium between desorption (removal) of soil from the fiber substrate into the detergent solution and its adsorption (re-deposition) from the solution onto the substrate. Such an equilibrium can be studied by chromatography where fiber substrate serves as the stationary phase and detergent solution as the mobile phase (3). During the development process of a 789

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A box-counting method for determining the fractal dimensions of crimped fibers is discussed in detail. Using nylon 6 crimped filament magnified figures, an application of the method is demonstrated where the box-counting dimension ( D B ) of nylon 6 has a distribution of 1.00-1.65. Eight animal fibers, cotton, and two other synthetic crimped fibers are also characterized by D B distributions of 1.00-1.32. Modified random Koch curves are used to simulate crimped fiber shapes and to examine the relationship between Hausdorff's dimension ( D H ) and D B .

Contact of fabric surfaces with human skin inevitably results in transfer of human sebum, which cannot be easily removed by washing the fabrics in water with conventional detergents (1). Sebum, the sebaceous secretion of the skin, consists of a complex mixture of triglycerides, squalene, cholesterol and other sterols, free fatty acids and aliphatic hydrocarbons (2) and is the major oily soil constituent in home laundry. Although many studies on the removal of sebum soil from different substrates have been reported, few address the thermodynamics of sebum soil removal from fiber substrates into aqueous surfactant solutions. The mechanism for removal of oily soil by a substratewater-micelle system can be considered a two-step process involving the transfer of soil from substrate to water (non-micellar phase) and then from water into micelles. Thus, the free energy change of soil determines whether a detergent process will be successful in removing the 167 JOS