Influence of the Dipole Moment on the Increase in the Thermal Conductivity of Thin Films Functionalized with Azo Dye

The functionalized polymers containing azobenzenes with different electron-donating and electron-withdrawing substituents in the form of a side-chain system were investigated using photothermal beam deflection spectroscopy (PBDS). The azopolymers were deposited on glass substrates using a spin-coating method with thicknesses below 450 nm. PBDS was used to determine the thermal properties of the prepared polymer samples. The topography of studied compounds was examined by atomic force microscopy (AFM). The obtained results showed the influence of the substituents in the polymer side chain on the thermal properties of studied materials. The thermal conductivity (K) extracted from PBDS measurements was found to range from 0.978 to 1.76 W m–1 K–1. Likewise, the thermal diffusivity changed from 0.663 to 1.16 mm2 s–1. The thicknesses of the samples were estimated based on ellipsometric measurements. The results of these studies show that by adding different substituents to azo-based polymers, the thermal conductivity can be effectively increased (slightly less than 1 order), which leads to better heat dissipation in devices made on its basis. These results enable the precise and sensitive analysis of thermal properties across a broad range of applications.