Thermophysical properties of methacrylic polymer films with guest-host and side-chain azobenzene

• Published in: Materials chemistry and physics 2019-02, Vol.223, p.700-707
• Main Authors: Trefon-Radziejewska, Dominika, Hamaoui, Georges, Chirtoc, Mihai, Horny, Nicolas, Smokal, Vitaly, Biitseva, Angelina, Krupka, Oksana, Derkowska-Zielinska, Beata
• Format: Article
• Language: English
• Subjects: Atomic force microscopy; Azo polymers; Azobenzenes; Glass substrates; Microscopy; Nanomaterials; Physics; Polymer; Polymer films; Polymers; Radiometry; Scanning thermal microscopy; Spin coating; Thermal conductivity; Thermal diffusivity; Thermal effusivity; Thermodynamic properties; Thermophysical properties; Thin films
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2018.11.054

The methacrylic polymer films containing azobenzenes with different peripheral substituents in the form of side-chain (P) and guest-host (A) systems were thermally investigated. The azo polymers with thicknesses below 1 μm were deposited on glass substrates using spin coating method. Photothermal radiometry (PTR) and scanning thermal microscopy (SThM) were used for determination of thermophysical properties of polymer samples. The topography of studied compounds was examined by atomic force microscopy (AFM). The results showed the influence of peripheral substituents as well as that of the polymer system on the thermophysical properties of studied azo polymers. Thermal diffusivity (α) extracted from PTR measurements is between 5.56 10−8 m2s−1 and 11.3‧10−8 m2s−1 for A samples, 2.76‧10−8 m2s−1 and 7.62‧10−8 m2s−1 for P samples depending on the substituent. Likewise, thermal effusivity (ε) changes from 474 Ws1/2m−2K−1 to 532 Ws1/2m−2K−1 for A, and from 473 Ws1/2m−2K−1 to 564 Ws1/2m−2K−1 for P samples. The volumetric heat capacity (Cv) and in-depth thermal conductivity (κ) were calculated on the base of PTR results. Local κ obtained from SThM measurements is between 0.15 Wm−1K−1 and 0.22 Wm−1K−1 due to different substituents and polymer system. Thermal studies performed in this work provide valuable information for engineers designing azobenzene polymer thin films based devices and supplement the knowledge of their thermal behavior in the system. •Thermophysical characterization of methacrylic polymer films with guest-host and side-chain azobenzene.•Local thermal conductivity determination of azobenzene-containing polymer films by scanning thermal microscopy.•Thermal diffusivity and effusivity determination of azobenzene-containing polymer films by photothermal radiometry.•Influence of peripheral substituents and polymer system on thermophysical properties of azo polymer films.