Abstract: In this work, in-plane and through-plane thermal diffusivities and conductivities of a freestanding
sheet of graphene nanoplatelets are determined using photothermal beam deflection spectrometry.
Two experimental methods were employed in order to observe the effect of load pressures
on the thermal diffusivity and conductivity of the materials. The in-plane thermal diffusivity was
determined by the use of a slope method supported by a new theoretical model, whereas the
through-plane thermal diffusivity was determined by a frequency scan method in which the obtained
data were processed with a specifically developed least-squares data processing algorithm.
On the basis of the determined values, the in-plane and through-plane thermal conductivities and
their dependences on the values of thermal diffusivity were found. The results show a significant
difference in the character of thermal parameter dependence between the two methods. In the case
of the in-plane configuration of the experimental setup, the thermal conductivity decreases with the
increase in thermal diffusivity, whereas with the through-plane variant, the thermal conductivity
increases with an increase in thermal diffusivity for the whole range of the loading pressure used.
This behavior is due to the dependence of heat propagation on changes introduced in the graphene
nano-platelets structure by compression.Keywords: graphene nanoplatelets, thermal diffusivity, thermal conductivity, photothermal spectrometryPublished in RUNG: 30.11.2021; Views: 1652; Downloads: 62 Link to full textThis document has many files! More...