Proton exchange between spin groups of the solid matrix of hydrated granular potato starch and water was studied using the 2D time domain NMR. The proton spin-spin relaxation time T_2, and spin-lattice relaxation time T_1 (selective and non-selective pulse sequences) were measured at room temperature. The observed spin relaxation results were analysed for exchange assuming a two-site exchange model (between water and solid matrix of starch). In this analysis we determined the intrinsic spin-lattice relaxation time for water protons (49 ms) and solid starch matrix protons (172 ms), as well as the water-starch magnetization exchange rate (86 s^{-1}).
Small-angle X-ray scattering experiments were carried out on cellulose membranes obtained by phase inversion from a solution of the polymer in 1-ethyl-3-methylimidazolium acetate, by coagulation in water and selected primary alcohols. The invariant, Q, and the Guinier radius, R_{G}, computed directly from the small-angle X-ray scattering curve allowed us to estimate the pore dimensions and the pore volume fraction. It was found that both content and dimensions of pores depend on molecular mass of the coagulant used. Also, it was found that the dipole moment of coagulant molecules has a large influence on the volume content of the pores.
In structural studies on biological materials, among other methods, electrical techniques are used widely. Temperature dependence of electrical conductivity is a method permitting studies on denaturation, glass transition and water release - processes, which occur in solid-state proteins. Variations of amplitude and temperature of the peak on the recorded thermogram make it possible to draw conclusions about thermal stability and physicochemical processes occurring in the studied biological material. The shape of experimental curve is material-related and depends upon its "history". The paper is based on experimental results obtained mainly for collagen.
1D photonic crystal was fabricated in a dichromate-sensitized biopolymer using holography method. The effects of the temperature of the photonic crystal layer on the center of photonic band gaps were studied. We showed that the central wavelength of the band gap can be tuned by heating the photonic crystal layer. By applying such heat treatment, tuning of the position of the band gap for about 80 nm was obtained.
The paper highlights versatility of high-energy milling in engineering of different functional materials using three approaches which give the benefits as green processes. They are: direct mechanosyntheses, modification of properties and activation of solids by co-milling procedures. The examples are presented.
Within this study we use methods such as spectral analysis that gives the spectral coefficient β, detrended fluctuations analysis that gives the scaling exponent α and the determination of Hurst exponent (H) to analyze the spatial series corresponding to the temperature factors of N, C-alpha, C and O atoms of 14 complexes of the chicken lysosyme. The mean values of the investigated parameters obtained for the 14 complexes are: β=1.779 ± 0.086, α=1.382 ± 0.009 and H=0.916. These values reveal long-range correlation in atomic vibrations corresponding to the chicken lysozyme backbone.
In this work, the electrophoretic deposition method has been developed for the fabrication of bioactive alginate coatings on the surface of Ti15Mo implant alloy. Thin ZnO film was deposited cataphoretically as the interlayer prior to anaphoretic deposition of alginate (Alg) which was performed from aqueous solution containing 1 g dm^{- 3} of NaAlg at room temperature. The deposition voltage and time varied in the range 20-50 V and 30-120 min, respectively. The microstructure of Alg coatings was studied by scanning electron microscope, and the surface roughness was analysed using atomic force microscopy. Structure was studied by grazing incidence X-ray diffraction. Chemical composition and functional group were examined using energy dispersive spectrometry and attenuated total reflectance Fourier transform infrared spectroscopy methods, respectively. It was found that controlling the deposition conditions it is possible to obtain amorphous Alg coatings of variable thickness and porosity. Mechanism of electrophoretic deposition of bioactive Alg coatings on the Ti15Mo alloy surface was discussed.
In this short paper we illustrate the versatility of positron annihilation lifetime spectrometry when used for material characterisation by presenting a selection of recent lifetime studies carried out on novel polymeric materials with a wide range of potential industrial applications. We highlight the importance of local free volume in governing the macroscopic properties (e.g. permeation properties, mechanical strength) of these materials and how lifetime measurements can be used in conjunction with a number of complementary techniques in order to establish composition-structure-property relationships for these systems.
Positron annihilation lifetime spectroscopy was applied to investigate the microcapsules composed of n-eicosane (filling material) and polysiloxane polymer (shell) in the range of temperatures 123-333 K. Pure components of microcapsules were also investigated as a base for interpretation of the measurement results. The temperature of phase transitions in microcapsules was determined. It showed the appearance of a rotary phase, which is not present in pure n-eicosane. In the considered material, two types of free volume have been identified. The sizes of free volumes able to accommodate Ps were estimated using standard models. On the basis of the o-Ps intensities, the content of polysiloxane in microcapsules was estimated as about 40%. Internal structure of the microcapsules (morphology) was observed by scanning electron microscopy.
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