Title Characterization of weak polyelectrolytes in aqueous solution - charge and isoelectric point in dependence on the molecule structure
Date 19.05.2017
Number 52526
Abstract The topic of this work was the characterization of unmodified poly (ethylene imines) (PEI)s in comparison with different oligosaccharide<br />(OS)-PEI-modified dendritic polymers (OM-PEI) using polyelectrolyte titration. It was found that the charge density (CD) as well as the<br />isoelectric points (IEP) was strongly influenced by the details of modification such as the type of oligosaccharide (Lactose or Maltose),<br />its structure and size (Maltose, Maltotriose or Maltoheptaose) and the PEI-OS ratio. Whereas the charge of unmodified PEI is cationic up<br />to pH of about 10, that means IEP of about 10, the IEP decreases with the influence of substituents. Further it is shown that the higher the<br />degree of chemically coupled OS units on the PEI surface, the lower is the charge density. For OM-PEIs the endpoint of titration<br />depended on the speed of titration which is consistent with a relatively slow rate of forming poly-ion complexes between modified PEIs<br />and titrants. For a good reproducibility the titration velocity should be not too high. Therefore a manual titration regime should be<br />preferred instead of an automatic “standard” titration regime with high titration velocity.
Publisher Biointerface Research in Applied Chemistry
Identifier 0
Citation Biointerface Research in Applied Chemistry 7 (2017) 1931-1938
Authors Petzold, G. ; Steinbach, C. ; Loos, A. ; Schwarz, S.
Tags poly(ethylene imine) characterization polyelectrolyte titration charge density

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