Particle/applicator interactions in household surface cleaning

Despite the wide use of household cleaning fluids, fundamental understanding of their performance is not extensive. Aside from the chemical compounds, abrasive particles are often integrated in cleaning fluids to increase their capacity to remove soil from surfaces. The mechanical actions of the particles (which operate in conjunction with a suitable applicator under a certain load) typically result in two wear phenomena: “grooving abrasion”, where particles act as if they are part of one of the sliding surfaces and “rolling abrasion”, where particles can roll and slide between the two sliding surfaces. Unfortunately, the ability to remove material from a surface influences both the effectiveness of a cleaning fluid in removing stain and its capacity to damage the underlying surface. Therefore, the behaviour of such particles needs to be understood and predicted to optimise cleaning fluid performance. The aim of this work was to investigate the interaction between the amount of material removed from a typical household surface, and fundamental factors such as applied load, the size of the abrasive particles and their concentration within the carrier fluid. In order to do so, an analytical model was developed to predict the material removal rate of a set of abrasive particles. The model predicts the behaviour of particles of different sizes, suspended in pure water at varying concentrations, when a vertical load is exerted on the applicator. In order to assess the effectiveness of the model, a test rig was developed to simulate a typical cleaning process, which involved using different sizes and concentrations of particles suspended in water over a test surface made of PMMA. These cleaning experiments allowed data collection on material removal which was used to validate the results obtained from the analytical model.