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DNA complexes with cetyltrimethylammonium chloride (CTMA), benzyldimethylhexadecylammonium chloride (BAC) and hexadecylpyridinium chloride (HDP) surfactants as powder samples were studied by Fourier-transform middle infrared spectroscopy, X-ray diffraction and dielectric spectroscopy methods. Complexation as electrostatic interactions was confirmed by FT-MIR spectroscopy. The width of DNA-surfactant complexes was estimated to 61–73 Å based on modeling with the semi-empirical PM7 method. Based on SAXS results we propose the packing model for the complex molecules as hexagonal or slightly distorted hexagonal depending on the surfactant. For the first time the dielectric process registered in the low frequency range for all complexes was interpreted as oscillation of surfactant ions (BAC+, HDP+ or CTMA+), analogous to the oscillation of ions (e.g. Na+) in solutions of pure DNA. The influence of the structure of the complex-forming surfactant molecule on the value of the relaxation time distribution parameter is discussed. [Display omitted] • Native DNA is mainly characterized by B-conformation, while in complexes with surfactants it has A-conformation. • DNA-CTMA complex have a hexagonal structure, while DNA-BAC and DNA-HDP a slightly distorted hexagonal structure. • The relaxation process for DNA-surfactant complexes is connected with the oscillations of the surfactant functional groups. [ABSTRACT FROM AUTHOR]

A non-isocyanate poly (hydroxyurethane) network was synthesized by reaction of a tricyclic carbonate compound with diamines. The system was modified by two types of Polyhedral Oligomeric Silsesquioxane (POSS) molecules, one retaining the crosslinked nature of the system, and another effectively loosening it. We studied water absorption as a function of environmental humidity and observed that all systems are extremely hydrophilic, absorbing up to 65% of water when exposed to 97% environmental humidity. In parallel, using differential scanning calorimetry and dielectric spectroscopy, we studied the effects of POSS and the significant plasticization caused by absorbed water on the glass transition and charge mobility. In dry materials, crosslinking POSS seems to reinforce the matrix and at least initially slow down mobility while the opposite effect is observed for the moiety that loosens the network. Both POSS inhibit plasticization, both indirectly by inhibiting water absorption, and directly, by stiffening the network, especially in the case of crosslinking POSS. [Display omitted] • Non-isocyanate poly (hydroxyurethane)s networks are very hydrophilic polymers. • Absorption of aater causes extreme reduction of T g. • POSS affect glass transition of these networks in ways dependent on the topology. • POSS affect the water absorbing capacity of the networks. [ABSTRACT FROM AUTHOR]