Imaging the Detergency of Single Cotton Fibers with Confocal Microscopy: the Effect of Surfactants and Lipases

Abstract

AbstractDetergency mechanisms of lipids from single cotton fibers were visualized by means of confocal laser scanning microscopy (CLSM). Fibers were soiled with different types of lipids: olive oil, lard and tri‐C10, and subsequently stained with the fluorescent probe Nile Red. A surfactant composition of 300 μM C12E6/LAS (1:2 mol%) was used to mimic the surfactants used in a common washing solution. It was evident from the captured image series that the different kinds of soiling were removed by different mechanisms by the surfactants, depending on the fluidity of the lipid. Roll‐up was the main mechanism when removing olive oil, whereas emulsification (necking) and/or solubilization were observed in the removal of lard and tri‐C10. Only 20–25% of the olive oil remained after treatment with surfactants, which was much less compared to the solid fats where roughly 50% remained at end of treatment. The effect of adding lipases to the detergent formulation was clearly seen, both by an apparently higher rate of removal of olive oil but also using double injection when removing lard. A first injection of only surfactants removed a certain part of the lard as emulsion droplets stuck onto the fiber. A second injection of both lipases and surfactants was able to remove some of the preformed emulsion particles and reduce the overall remaining lard content on the cotton fiber.