Naslov
Effect of Polyelectrolyte Charge Density on the Interactions in Carrageenan-Dodecylammonium Chloride Mixtures

Autori
Vinceković, Marko ; Bujan, Marija

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Sažetci, Abstracts / Zrnčić, Hrvoje - Zagreb, 2003, 115-115

Skup
XVIII. Hrvatski skup kemičara i kemijskih inženjera

Mjesto i datum
Zagreb, Hrvatska, 16.02.2003. - 19.02.2003

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
charge density; polyelectrolytes; surfactants

Sažetak
The strength and the nature of interactions between water soluble polyelectrolytes and oppositely charged surfactants depends on the characteristics of both the polyelectrolyte and the surfactant. With respect to the polyelectrolyte, factors such as surface charge density, type of charges, flexibility, conformation, degree of polymerization and the presence and distribution of hydrophobic and hydrophilic segments are crucial. The effect of charge density on the polyelectrolyte-oppositely charged surfactant interaction is often difficult to isolate from other factor, especially the hydrophobic interaction between polymer backbone and the surfactant. In the present work a series of biopolymeric polyelectrolytes, carrageenans, with increasing linear charge density, and cationic surfactant, dodecylammonium chloride (DDACl) were investigated by conductometry, potentiometry, surface tension, light scattering and microelectrophoretic measurements. The structures of the three main forms of carrageenans differ only in the number of sulphate groups per disaccharide ; kappa has one, iota has two and lambda has three sulphate groups. It is shown how difference in charge density lead to a wide variation in surfactant monomers adsorption to polyelectrolyte chains and phase separation properties. For a given DDACl concentration the adsorption equilibrium varies considerably between the three carrageenan samples used. It is strongest for the lambda sample. Electrostatic and hydrophobic interactions between DDACl and the different types of carrageenans resulted in a more or less complete shrinking of the carrageenan gel, depending on DDACl concentration, and in the formation of a bilayers structure ; i.e., vesicles. Increasing the charge density of the polymer chain and increasing the polymer concentration improved the degree of ordering in the resulting carrageenan-surfactant complexes.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

POVEZANOST RADA