Naslov
Nano- and Microcomplexes of Biopolymer and Surfactants

Autori
Vinceković, Marko ; Bujan, Marija

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

Izvornik
ICPPC-2010 / Thomas, Sabu - Kottayam : Mahatma Gandhi University, Kottayam, 2010, 158-158

Skup
Second International Conference on Polymer Processing and Characterization

Mjesto i datum
Kottayam, Indija, 15.01.2010. - 17.01.2010

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
biopolymers; surfactants; complexes

Sažetak
Active research in the recent past in the field of oppositely charged biopolymers/surfactant interactions has provided many new insights into the phase behavior and formation of various nano- and microstructures. Despite extensive research, the molecular basis for the phase transitions in solutions that result in complexation, aggregation or gelation, is not yet completely understood. In order to establish the relationship between molecular structure/reactivity in mixtures containing ionic surfactant and oppositely charged biopolymers, various methods were used to determine key structural features at the nano- and meso-length scale. Differently charged carrageenans (k-, i- and λ-carrageenan) and dodecylammonium chloride in water solution were used as model systems. Interactions between a polyelectrolyte and an oppositely charged surfactant are characterized by the fact that the complexation takes place in a highly cooperative manner. Formation of various complexes at the air/solution interface and in the bulk solution (from nano- to microdimensions), precipitation and gelation strongly depends on carrageenan and surfactant concentrations, their molar ratio and charge density on carrageenan chains. Main factors governing complexation are electrostatic and hydrophobic interactions as well as conformation of the carrageenan chains. With increasing carrageenan concentration, the intra-macromolecular complexes change to inter-macromolecular, which subsequently reorganize into better ordered structures, giant vesicles and precipitate - dodecylammonium carrageenate. Structural analysis of the new compounds revealed the formation of a lamellar structure with the polar sublayer containing of carrageenan chains and the nonpolar sublayer consisting of disordered dodecylammonium chains electrostatically attached to the carrageenan backbone. At gelling carrageenan concentration, progressive addition of dodecylammonium chloride caused gradual break down of the gel network and in micellar region gel collapsing. Gradual transitions from the structure of carrageenan gel alone to lamellar ordering of collapsed gel are balanced by intermolecular forces within the gel network ; i.e. by hydrogen bonding, electrostatic, hydrophobic, and Van der Waals forces.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

POVEZANOST RADA