Hildebrand Solubility Parameters

• is the solubility parameter. (Solubility parameter data available.)
  
  
• There are three dimensional solubility parameters: that is to say, the solubility parameter is an array of three numbers:
  
  
  1. a number for dispersive forces present
  2. a number for dipole-dipole forces
  3. a number for hydrogen bonding forces
     
     
  Note that with hydrogen bonding, it doesn't take place unless the solvent has the right chemistry for hydrogen bonding.
  
  
• Three dimensional solubility parameters can be plotted on a three dimensional graph, where each of the axis is one of the three types of forces listed above. Send me email if you know where I can get a copy of such a graph to scan in and place here.
  
  
  Feedback received: Thanks, Mark!
  Try the following reference:
  M. H. V. Mulder, et. al, Journal of Membrane Science, 11 (1982) 349-363.
  
  compliments of:
  
  Mark Stone
  Idaho National Engineering Laboratory
  
  
  

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• is the change in enthalpy of mixing and V(mix) is the total volume of mixing.
  
  
• is the volume fraction of solvent. is the volume fraction of polymer.
  
  
• is the solubility parameter of the solvent. is the solubility parameter of the polymer.
  
  
• Note the obvious (below) that a solubility parameter is the square root of cohesive energy density for the material in question.

  Cohesive Energy Density

  Cohesive Energy Density is the energy needed to remove a molecule from its nearest neighbors. At least that is what [Stevens-43] said; on inspection of the equation, which has units of energy on top, and units of volume on the bottom, I would say it should read "Cohesive Energy Density is the energy needed to remove a molecule from its nearest neighbors, divided by the total volume of the moved molecule." Soon, hopefully, a reference I find will back this up.
  
  
  
  

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Last Update- January 15, 1995- wld

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