Fig. 3.

a Variations of the axial k of an infinite one-dimensional PE chain as a function of temperature, along with the absolute k contributions from the four acoustic phonon modes and the k values from the single-mode relaxation-time model. TA1 and TA2 are the two transverse phonon modes vibrating perpendicular to the chain axis, TWA is the twisting mode and LA is the longitudinal mode.

Reproduced with permission from Ref. [31]. Copyright 2017, American Chemical Society. b k of PE nanofiber as function of temperature. Reproduced with permission from Ref. [3]. Copyright 2018, Springer Nature. c Ratio of k of thin PE films to k of PE bulks as function of thickness dependence. Reproduced with permission from Ref. [33]. Copyright 2021, American Physical Society