Journal Article

FZJ-2019-01045

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Phase Behavior and Microstructure of Symmetric Nonionic Microemulsions with Long-Chain n -Alkanes and Waxes

Schneider, K. ; Ott, T. M. ; Schweins, R. ; Frielinghaus, H.FZJ* ; Lade, O. ; Sottmann, T. (Corresponding author)

2019
Soc.79045 Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/21728  doi:10.1021/acs.iecr.8b04833

Abstract: Microemulsions are thermodynamically stable, macroscopically isotropic mixtures of at least two immiscible components and a surfactant. Their general features, i.e. the complex phase behavior, the ultralow interfacial tensions, and the multifarious nanostructure, have been systematically elucidated in the last century. However, the efficient solubilization of long-chain n-alkanes and waxes, which plays a significant role in enhanced oil recovery, washing, and cosmetics, remains a challenge. Thus, in this work the influence of the n-alkane chain length k on the phase behavior of ternary (symmetric) microemulsions containing equal volumes of water and oil was studied. Using n-alkanes ranging from n-dodecane (C12H26)ton-dotriacontane (C32H66) and pure n-alkyl polyglycol ether (CiEj) surfactants, we found that the efficiency of the respective surfactant decreases linearly with increasing k, while the phase inversion temperature (PIT) shows a logarithmic dependence. The influence of a technical wax on the phase behavior was studied by means of the systems H2O−SASOLWAX 5805 (Sasol)−C16E6 yielding an equivalent alkane carbon number (EACN (SASOLWAX 5805)) of 30.8. Finally, the pure CiEj surfactants were replaced with technical grade counterparts of the Genapol series (Clariant) finding that the solubilization efficiency of the long-chain Genapol O 080 is comparable to the pure C16E6 surfactant. Using small-angle neutron scattering (SANS) the microstructure of the formulated microemulsions was studied near the so-called optimum (X̃ ) point. The scattering curves prove that microemulsions containing long-chain n-alkanes and waxes are also bicontinuously structured at the phase inversion temperature (PIT). Interestingly, a high degree of structural ordering is found reflected by values of the amphiphilicity factor fa ranging between −0.83 and −0.87.

Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Soft Condensed Matter (2nd) ; Chemistry (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS-FRM-II)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)

Research Program(s):

1. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)
2. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)

Experiment(s):

1. KWS-1: Small angle scattering diffractometer (NL3b)

Appears in the scientific report 2019

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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