Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2005-2-7
pubmed:abstractText
The complex formation between nonionic alkyldimethylamine oxide (CnDMAO, n=14, 16, and 18) and sodium palmitate (NaPa) in the solid phase of CnDMAO/NaPa mixtures and the dependence of the interaction parameter beta of the regular solution theory (RST) on the mixed micelle composition of C16DMAO/NaPa mixtures were investigated. The dissolution temperature showed a maximum at a NaPa mole fraction X(Pa)(*) of 0.3-0.4 for C16DMAO/NaPa and 0.2 for C18DMAO/NaPa. The compositions of the complexes suggested by X(Pa)(*) are C16DMAO: NaPa=3:2 or 2:1 and C18DMAO:NaPa=4:1. The composition X(Pa)(*) depended on the chain length of the amine oxides. The maximum was not observed in the case of the C14DMAO/NaPa/water system. In the range 0.7< or =X(Pa)< or =1.0, dissolution temperature depression was observed with decreasing X(Pa). The dissolution temperature depression was analyzed by taking into account the nonideal behavior in the mixed micelles and the counterion binding on the mixed micelle surface. The negative beta values were obtained for all three mixed systems. It was shown that the counterion activity remained practically constant in the range of 0.7< or =X(Pa)< or =1.0. The cmc values of C16DMAO/NaPa mixtures were determined by pyrene fluorescence measurement. For C16DMAO/NaPa mixtures, the dependence of the RST interaction parameter beta on the mixed micelle composition X(Pa) was determined for a wide range (0.2< or =X(Pa) < or =0.9). In the range 0.2< or =X(Pa)< or =0.5, the beta values were obtained from an analysis of cmc based on the RST. In the range 0.7< or=X(Pa)< or=0.9, the beta values were obtained from an analysis of the dissolution temperature depression. From the analysis of the micelle composition dependence of the beta values, a short-range attractive interaction between the headgroup of C16DMAO and palmitate anion is suggested.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9797
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
283
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
238-44
pubmed:dateRevised
2009-11-11
pubmed:year
2005
pubmed:articleTitle
Complex formation in alkyldimethylamine oxide/sodium palmitate/water mixtures.
pubmed:affiliation
Department of Chemistry and Physics of Condensed Matter, Graduate School of Sciences, Kyushu University, 33 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
pubmed:publicationType
Journal Article