APPLICATION OF (DN/DC)-DATA FOR THE DETERMINATION OF PARTIAL SPECIFIC VOLUMES, FREE SOLUTE AND BULK VOLUMINA AND OF SOLUTE-SOLUTE AND SOLUTESOLVENT INTERACTIONS.
Abstract
The principles of a method are outlined whereby one can determine both the partial specific volume of a solute, V, and its refractive index, n2, by means of interferometric measurements of (dn/dc) using a suitable (dn/dc)-expression in conjunction with both the one component ClausiusMosotti equation and a simple graphical interpolation procedure. The method is applicable if the polarizability of both solvent and solute molecules is unaffected by the solution process. It is tested successfully on solutions of polystyrene in various solvents where the optical V-data agree to within better than 2% with densitometric V-data given in the literature. It follows from the data that dissolved polystyrene contains up to 2% of free volume, the exact amount depending on both interaction parameters and on hitherto neglected steric factors. The variation, with temperature, of the free solute volume, also derived by means of the new method, leads to the prediction of a 'molecular melting point' and a 'molecular glass transition temperature' for isotactic and branched chain polymers respectively dissolved in suitable solvents. The possible promise of the method for differentiating between straight chain and branched chain polymers and for studying helix-coil transitions and equilibria and changes in molecular solvation are briefly discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 22, 1965
- Accession Number
- AD0460469
Entities
People
- Wilfried Heller
Organizations
- Wayne State University