Young—Dupre’s equation

By measuring the contact angles between the polymer and various liquids, it is possible to calculate the proportion of surface energy effect in the initial retractive stress using Young-Dupre s equation, the value is around 0.3 After six minutes of relaxation, it increases to 0.5 ... 

Finally, by substituting for the interfacial tension from the modified Young s equation (Eqn (3.12)) into the work of adhesion (Eqn (3.20)) for a solid—liquid system, the equation for the work of adhesion can be simplified to Eqn (3.21), also known as Young— Dupre s equation. 

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