Effect of Solvent on the Extension of High Polymer Molecule

Abstract

For clarifying the physical properties of high polymer solution, it important to investigate into the relation of the extension of high polymer molecule in solution to the potential energies between chain elements of the high polymer molecule and solvent molecules. In the present paper is given a theoretical treatment of this relation as a guide to the experimental study.
The calculation is based on a lattice model. The potential energies of interaction between chain elements and solvent molecules were formulated as precisely as possible, and the expression for the extension of high polymer molecule was obtained.
The results secured may be summarized as follows: The expression by which the end-to-end distance of high polymer molecule is related to the potential energies between chain elements and solvent molecules, and also the expression for a change in end-to-end distance of high polymer molecule, when it is put from vacuum into solution, have been obtained. From these relations we see that the quantity which determines the extension of high polymer molecule in solution is ΔE=(E_pp+E_ss)⁄2−E_ps and the quantity which determines the change in extension accompanying the transfer of high polymer molecule from vacuum to solution is E_ps−E_ss⁄2. Here −E_pp, −E_ss, −E_ps are the potential energy between two chain elements, that between two solvent molecules and that between a chain element and a solvent molecule, respectively.