Oily Soil and Particulate Soil
YKI has a number of techniques available in house to study both oily soil and particulate soil removal. We frequently use surfactant affinity difference (SAD) concept and rapid formulation strategies to optimize new cleaning formulations for oily soil removal.
Dirt can be roughly categorized into oily soil and particulate soil. The removal of the oily soil is better understood and is generally considered to be easier than the removal of the particulate soil. This can be attributed to the heterogeneous nature of particles with varying surface energies, the fact that the particles can be trapped in pores on the surfaces, and the high attractive surface interactions between the particle and the surface.
Surface force technique
Concerning particulate soil removal YKI have, in collaboration with KTH, used the surface force apparatus to understand the interactions between a particle and a surface in dry contact. Two surfaces representing the soil particle and the soiled surface are put in contact in air. A cleaning solution is introduced between the surfaces and the (detachment-) force required to pull the surfaces apart is measured. A low detachment force implies efficient cleaning. The surface force technique also enables the study of protective coatings on surfaces to facilitate next time cleaning.
Resources
Cleaning efficiency and cleaning mechanisms have also been studied with the impinging jet and the quartz crystal microbalance with dissipation techniques (QCM-D). YKI has a Q-Sence E4 QCM-D apparatus, which enables simultaneous measurements of four different surfaces. This is a significant advantage to measure one experiment at a time and give substantially better statistics of the measured systems. YKI has also an in-house developed method to improve particle removal from hard surfaces where very clean surfaces are needed, in applications such as the electronics industries.