Sorption Equation
Three-parameter equations for moisture uptake allow for a more accurate description of fiber behavior across the entire humidity spectrum than simpler models. The guggenheim anderson de boer isotherm extends the basic multilayer sorption theory by adding a correction factor for the properties of the water molecules in the layers beyond the first. It is widely used for natural fibers that show complex bonding patterns with water.
Parameter Function
Constants within the formula represent the moisture content of the first molecular layer and the energy of the binding process. In the guggenheim anderson de boer isotherm, the third constant accounts for the difference between the bulk liquid state of water and the state of the water absorbed into the fiber. This detail improves the fit of the model at relative humidity levels up to ninety-five percent.
Textile Validation
Laboratory trials on silk and wool often use this equation to verify the effectiveness of water-repellent finishes. If the measured data fits the guggenheim anderson de boer isotherm closely, the chemist can determine how the finish has altered the internal surface area of the fiber. It provides a standardized way to compare the moisture capacity of different harvests of natural materials.
Model Validity
Calculation results are only defensible when the temperature remains constant during the data collection phase. Heat alters the kinetic energy of the water molecules, which changes the binding constants used in the equation. While the model is highly accurate for most textiles, it can fail for materials that undergo a phase change or dissolve when they become very wet.
