Studies in Newtonian Flow. III. The Dependence of the Viscosity of Liquids on Molecular Weight and Free Space (in Homologous Series)

Abstract

The free-space concept, previously applied to variation resulting from a change in temperature only, is here adapted to a case where both temperature and molecular weight vary. The molecular weight range of the n-paraffins illustrative of this case is limited to m=100 through m=240. Over this range of molecular weights the family of lines represented by lnη=B(ν0/νf)+lnA intersects the vertical axis at very nearly a common point. By assuming a common intercept and representing the slopes of this family of lines in terms of molecular weight, an expression defining viscosity as a function of molecular weight and free space is deduced. This expression reproduces the ``selected data'' satisfactorily over the molecular weight range mentioned. Its greater significance as a step in the development of a far more useful function will become apparent in the succeeding paper.