The effect of pH and multivalent ions on the mechanical properties of gels with micellar nanodomains

abstrakt

angličtina

The aim of this study was to examine the properties and behaviour of phase-separated hydrogels. These can be prepared by interaction of specific biopolymer (sodium hyaluronate – Hya) with oppositely charged surfactant (carbethopendecinium bromide – Septonex). Using the method of rheology, the effect of pH and addition of multivalent ions to the mixture of Hya-Septonex, was studied. Samples underwent both oscillatory and flow measurements. Generally, pH suppressed the elasticity of Hya-Septonex hydrogels by decreasing both the elastic and viscous moduli in comparison to standard pH-uncontrolled samples. Molecular weight of polymer has also direct influence in presence of pH influence. Higher molecular weight of hyaluronan caused the elastic modulus to be higher than viscous even in case of lower pH. However, using the pH around or below the pKa of Hya (pH=3.5) caused that the most of the COO- groups of Hya were not dissociated, thus the gels were not formed. On the other hand, higher pH (pH=9) resulted in the most rigid hydrogels. The influence of multivalent ion environment on the rheological properties was also studied. Three representatives, Ca2+, Mg2+ and Fe3+, were selected for comparison. There was no significant impact on elastic and viscous moduli nor the flow behavior, compared to standard NaCl environment, with exception of Fe3+ ions. These samples evinced the highest values of elastic modulus leading to stiff, almost unmeasurable, hydrogels. The results of this work bring us closer to understand the properties and behaviour of these types of systems and their potential utilization in medical applications.

hyaluronan, surfactants, carbethopendecinium bromide, hydrogels, rheology

VELCER, T.; PEKAŘ, M.

17. 10. 2018

TANGER Ltd., Keltickova 62, 710 00 Ostrava, Czech republic, EU

Ostrava

978-80-87294-85-7

NANOCON 2018 - Abstracts

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