No effect of the hydrogen bonds on the physicochemical properties of the guest-host poly(amide imide) azosystems and efficiency of chromophore orientation

Abstract

In this paper, we show a series of the new noncovalent azosystems based on poly(amide imide) matrices. Azobenzene derivatives were attached to the polymer matrix via hydrogen bonds or formed doped systems. Additionally, glass transition temperatures of azosystems were established by the calculation procedure based on Fox equation. We proved that presence H-bonds between polymer matrix and chromophore does not effect on increase Tg and T5, in comparison to the doped polymers. It was observed that poly(amide imide) matrices are able to the thermally induced intermolecular cross-linking via hydrogen bonds. Functional density theory (DFT) was used to observed both changes in geometry the polymer matrix before and after incorporation of the azo-dyes and H-bonds formation possibility. The presence of H-bonds both intermolecular and between polymer and chromophore was confirmed experimentally by FTIR and 1H NMR spectroscopy. The supramolecular system based on the matrix with pyridine rings in the side chains and 4-[(4-methyl phenyl)diazenyl]phenol was found to show a relatively efficient photo-orientation process. We showed the hydrogen bonds between chromophore and polymer matrix did not provide higher and more stable the photoinduced birefringence in comparison with doped one. It seems that the critical parameter which impacts on values and stability of Δn is azo-dye content.