Modelling of fractional relaxation behaviour characteristic in polysaccharide systems

Fractional calculus has become an important tool in the analysis of slow relaxation phenomena, such as stress-strain relationships in polymeric materials. The Zener model is an extension of the Maxwell model, which consists of a spring and dashpot in series, with an additional spring in parallel. A fractional rheological description is obtained by replacing the first order time-derivatives in the Maxwell-Zener equation with fractional derivatives of order q and micro. The fractional Zener model relating stress to strain is used to fit several experimental results on polysaccharide. The comparisons between the experimental results and the theoretical predictions are found to be satisfactory

Characterization of vesicles of nonionic surfactant mixtures

Nonionic surfactant vesicles are now widely studied as an alternative to liposomes. In the present work, the vesicles were prepared using mixture of nonionic surfactants and the optical microscope with cross polarizers was used in order to observe the vesicles and capture the image. The mixtures of nonionic surfactants Synperonic NP5-dodecyl-beta-D-glycopyranoside [DGP] were prepared for different mol ratio. The critical micelle concentration [CMC] of nonionic surfactant Synperonic NP5 was determined using the tensiometer with Du Nouy ring methods. The effect of different types of salt, namely; KCI, NaCI and CaCl in the CMC was also investigated. The critical vesicle concentration [CVC] for the nonionic mixtures was determined using UV-Visible Spectrophotometer at room temperature. The size of the vesicles of the nonionic mixtures was measured using particle sizer. The CMC and CVC of nonionic vesicles were found to decrease with salt concentration while, the size of the vesicles was found to increase with the salt concentrations. In addition, the rheological behaviours of the nonionic vesicles were investigated. The samples of vesicles showed liquid-like behaviours which were indicated by the domination of the loss modulus, G". The effect of salt concentrations and salt types in the rheological behaviours was also investigated. The dynamic moduli were found to decrease with salt concentration while the effect of the salt types in the elastic and storage moduli was not significant