Encapsulation of soils is indeed fundamental. The encapsulation is what is better known in other industries as anti-redeposition. The dirt is surrounded by surfactant molecules which have two ends - one attracted to water and the other to oil. The oil loving end (lipophile) basically sticks into the soil (most soils are oily) and the water loving end (hydrophile) dangles out in the water. With enough of these, the soil can be totally encapsulated and basically it becomes dissolved in water. This is a somewhat non-ionic process so soaps (which are ionic) operate a bit differently but this is a fair approximation.
Waterless or low water products really need something extra and this is where I am wary of them - not all such products actually incorporate that 'extra'. Think about it, the above is a process fundamentally concerned with oils. Yes, particulate soils can often be suspended because they are surrounded by oil which can in turn be surrounded by surfactant. However, this coating is not a rigid entity. Suspended particulate soils remain abrasive, the act of suspension is rarely adequate to stop a particle from abrading a surface when physical force is applied. Good practice would be to incorporate a component which inhibits the co-efficient of friction between any particulate matter and the surface. So now you have particulate matter which is suspended in the surface and a surface which may well actually repel particulate matter so effectively making it less abrasive.
Another point of for consideration/debate is that none of these products actually succeeds in total encapsulation. Were this the case, one would need only spray the product on and rinse (without contact). Whilst we can probably all appreciate that a high pressure wash will remove much of the dirt, it is very rarely completely efficient - a touchless wash remains a bit of an unreachable height in auto cleaning. What this tells you is that at least some of the dirt is still bonded to the surface after the wash product is applied. To remove it, one needs manual interaction so you are effectively 'ripping' unencapsularted dirt off the surface. Once in solution, it might become encapsulated quite rapidly but the unavoidable reality is that much of that dirt is briefly in contact with the surface with very little inhibiting the abrasive nature.
All of this is a bit of an aside really - but I admit to being a bit of surfactants 'geek' and I am sure someone out there might be interested to read some more of the detail!
