38. Solving a chemistry problem

3.15 Wetting of the glass surface with water changes with the introduction of a cationic surfactant, for example dodecylmethylammonium bromide. Plot the wetting isotherm /cosϴ=f(Cw)/, determine the wetting inversion point (cosϴ=0) and calculate the work of adhesion using the data below:
Spav, mmol/l 0 1*10-4 1*10-2 1 2 5 10
b, mJ/m2 72 71.5 70.1 63.2 56.2 50.9 41.0
ϴ, deg 0 47 85 92 82 57 0