Question

Difference between coefficient of friction and coefficient of adhesion

Answer 1

Ahesion is more or less straightforward if we want to glue together tow metarials. Peeling test works if one of the substrates is flexible. The physical picture is more or less clear. But how can one handle soft/soft surfaces e.g. between rubber and thermoplastic? There is no inteded adhesive layer, but there is some adhesion. If we want to move the two surcfaces against each other, we will experience resistance which depends on the medium, on the chemical composition of both components, on interfacial stress, complicated further by rate effects (stress relaxation etc.). The situation is even more complicated in biological systems. Here simple concepts as work of adesion (hysteresis), peeling etc. do not work. What are the best characterization techniques?
When we divide the mechanisms behind the sticking to two like; physical and chemical and then by thinking their sub-classes, it will be easier to analyze.
Chemical adhesion is irreversible in its own nature so separating two parts will definitely end-up with the fracture. It can be easily detected with solid NMR of a sample (as small as possible) from the interface, which will clearly show the changes of the chemical structure of the both surfaces and new arriving peaks as well. There is a small chance for ATR-FTIR if the there is not too much residue on the departed surfaces.
On the other hand, Physical adhesion is more tricky than the chemical ones. I will expect roughly three different mechanism for it.
Fist one is will be due to inter-molecular forces between two surface which will be easier to depart and even if there remains a residue the techniques above will definitely prove its true nature.

Answer 2

Answer:

" friction '' signifies sliding friction only. where T=Force necessary to start or to maintain movement. P=Normal Pressure. If T is taken as the force required to start the movement, po is called the coefficient of static friction or adhesion.

hope this helps you