spreading coefficient and its derivation

4. AF>CF
Adhesion forces are the forces of attraction between oil and
water while cohesion forces are forces of attraction between
oils

5. Wa- work of adhesion
Wc- work of cohesion
S = Wa - Wc
1

6. we will assume a hypothetical cylinder filled half with water
and half with oil.
Where:
-Wa is the work of adhesion used to break adhesive forces
between water and oil molecules
-Yo is the surface tension of oil
-Yw is the surface tension of water
Area =1cm2

7. Wa = YoA + YoW + YwA+ (-YowA)
Wa= YoA + YwA – YowA
Wa = Yo + Yw - Yow 2

8. Wc = Yo A + Yo A
Wc = 2Yo A
Wc = 2Yo 3

9. S = Wa - Wc
Wa = Yo + Yw - Yow
Wc = 2Yo
1
2
3
S= (Yo + Yw – Yow ) – 2Yo
S=Yw - Yow – Yo
S= Yw –(Yow - Yo )