Fagkonferansen
i Budapest omhandler fremlegg av forskningsresultater innenfor overflate- og
kolloidkjemiske problemstillinger inkludert en del nanoteknologi.
Konferansen ble avholdt fra og med mandag 18.09 til og med fredag 22.09. Hver
dag består av to plenarforedrag og en rekke kortere innlegg med to parallelle
sesjoner. I tillegg kommer plakatforedragene som avholdes på ettermiddag og
kveldstid. Vi hadde et plakatforedrag første dagen. Konferansen hadde 425
påmeldte deltakere. Nedenfor er sammendraget fra vårt bidrag presentert. Dette
er nødvendigvis skrevet på Engelsk:
* Institute for Aquaqulture- Chemistry- and Biochemistry subjects, Faculty
of Engineering,
**Department of
Chemistry,
The formation of micelles is aided by a cooperative
interaction due to van der Waals forces
between the hydrocarbon chains of the surfactant molecules. The same
interaction is believed to be responsible for the formation of surfactant
aggregates on solid surfaces. Previous data has shown a broad variation in the
structure of these adsorbed aggregates depending on the system studied (1-3).
However, the interior of the aggregates is extremely similar to those of a
micelle. This gives an excellent situation for incorporation of hydrophobic
components just as ordinary micelles are known to do.
Here,
the adsorption of the surfactant, dodecyltrimethylammonium
bromide (DTAB) and the co-adsorption of the
additives, phenol and benzyl alcohol, onto silica is investigated. With a
constant DTAB concentration and varying alcohol
concentration the results show an increasing adsorption of alcohol with
increasing alcohol concentration. In the solution containing a phenol
concentration of
The
adsorption density of DTAB onto silica is found to increase
at low phenol and benzyl alcohol concentrations before a maximum in the
adsorption is reached at an alcohol concentrations of about 0.05M. At the
maximum surfactant adsorption density, the mole-ratio of alcohol to surfactant
on the silica surface is approximately 1.0. A further increase in the
concentration of the alcohols gives a readily decrease in the adsorption data
of the DTAB while the adsorption of alcohol continues
to increase. However, the slope of the line, when plotting the alcohol adsorption
capacity against the alcohol concentration, decreases as the alcohol
concentration increases. The result indicates that the surfactant aggregates
increases and becomes large mixed surfactant-alcohol aggregates when alcohol is
added in the low concentration range. In the higher concentration range, where
the alcohol continues to adsorb while the surfactant starts to desorb, the mixed aggregates seem to contain several
alcohol molecules for each surfactant molecule.
References