Prediction of Discontinuous Volume Phase Transition with Respect to Temperature

3 Prediction of Discontinuous Volume Phase Transition with Respect to Temperature 

Swelling experiments are usually conducted in a solution. In this case, the isobar condition is automatically attained, i.e. II = 0. The phase diagram is then calculated from Eq. (2.12) by imposing the condition, IT = 0 

More explicitly the temperature at which the osmotic pressure is zero, Tn = o is given as a function of the degree of swelling, (t) o/ j ) = V/V0, as follows 

The osmotic modulus becomes zero at the spinodal point. Therefore, the spinodal temperature, Ts, is obtained by substituting K = 0 into Eq. (220) 

The scaling arguments simplify the expression of the osmotic pressure (or the osmotic modulus) by extracting the important terms in Eq. (2.12) and by taking account of the excluded volume effect of the network chains as follows 

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