A theory for the temperature effect on the chain length dependence of the diffusivity of oligomers

The effect of temperature on the chain length (N) dependence of the diffusivity of oligomers (with N = 10-60 carbon atoms) was theoretically studied using the free volume theory of Wong and Choi [Soft Matter, 2019, 15, 9300-9309] along with the experimental data of von Meerwall et al. [J. Chem. Phys., 1998, 108, 4299-4304]. Experimental data showed that D_cm∼N^v and that becomes less negative as temperature increases but is always stronger than -1 as obtained in the Rouse model. The theory successfully predicts the exponent v as a function of temperature.