Effects of Membrane Preparation and Posttreatment Parameters on the Nodular Size

4 Effects of Membrane Preparation and Posttreatment Parameters on the Nodular Size 

Evaporation temperature °C Average nodule diameter (nm) Mean roughness (nm) 

The temperature difference between the top and the bottom of the cast film, AT, is calculated by two equations (Eqs. 4.1 and 4.2)  

It should be noted that the cast solution is considered to be very dilute in this calculation. Equation 4.1 is based on the steady-state diffusion of solvent vapor through stagnant air [72], and Eq. 4.2 is based on the heat balance. 

The Marangoni number based on the surface tension is given as 

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