Another way to quantify the 18-MEA arrangement in water is through their tilt angles relative to the hair fiber surface. In the absence of a solvent, the 18-MEA layer is disordered as shown by a reduced thickness relative to an ordered monolayer . The resulting tilt angles in vacuum range form 60-90 degrees relative to the normal vector of the xy plane. Increased damage results in tilt angles close to 90 degrees, suggesting 18-MEA is laying down on the surface (Figure ). In the presence of water, the 18-MEA inter-lipid interactions become more favorable, broadening the tilt angle distribution regardless of 18-MEA surface density in our models. While the virgin hair surface distribution remains relatively unchanged in the presence of water, minus a slight decrease in the population close to 90 degrees, the peak of the tilt angle distribution for both lightly and moderately damaged hair surface models decreased. It would appear the rearrangement for lightly damaged and virgin surfaces is similar as the tilt angle distributions have the same overall shape. Visual inspection of the surfaces show more surface area exposure of KAP5-1 in the moderately damaged model when compared to the other two systems. This agrees with a higher tilt angle distribution observed when two-thirds of 18-MEA are removed from the surface. A similar observation was made in coarse grain hair models containing various degrees of damage .