Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

David Cabaleiro, Samah Hamze, Filippo Agresti, Patrice Estellé, Simona Barison, Laura Fedele and Sergio Bobbo
Additional contact information
David Cabaleiro: Université Rennes 1, LGCGM, EA3913, F-35704 Rennes, France
Samah Hamze: Université Rennes 1, LGCGM, EA3913, F-35704 Rennes, France
Filippo Agresti: Institute of Condensed Matter Chemistry and Technologies for Energy, National Research Council, I–35127 Padova, Italy
Patrice Estellé: Université Rennes 1, LGCGM, EA3913, F-35704 Rennes, France
Simona Barison: Institute of Condensed Matter Chemistry and Technologies for Energy, National Research Council, I–35127 Padova, Italy
Laura Fedele: Institute of Construction Technologies, National Research Council, I–35127 Padova, Italy
Sergio Bobbo: Institute of Construction Technologies, National Research Council, I–35127 Padova, Italy

Energies, 2019, vol. 12, issue 17, 1-19

Abstract: This work analyzes the dynamic viscosity, surface tension and wetting behavior of phase change material nano–emulsions (PCMEs) formulated at dispersed phase concentrations of 2, 4 and 10 wt.%. Paraffin–in–water samples were produced using a solvent–assisted route, starting from RT21HC technical grade paraffin with a nominal melting point at ~293–294 K. In order to evaluate the possible effect of paraffinic nucleating agents on those three properties, a nano–emulsion with 3.6% of RT21HC and 0.4% of RT55 (a paraffin wax with melting temperature at ~328 K) was also investigated. Dynamic viscosity strongly rose with increasing dispersed phase concentration, showing a maximum increase of 151% for the sample containing 10 wt.% of paraffin at 278 K. For that same nano–emulsion, a melting temperature of ~292.4 K and a recrystallization temperature of ~283.7 K (which agree with previous calorimetric results of that emulsion) were determined from rheological temperature sweeps. Nano–emulsions exhibited surface tensions considerably lower than those of water. Nevertheless, at some concentrations and temperatures, PCME values are slightly higher than surface tensions obtained for the corresponding water+SDS mixtures used to produce the nano–emulsions. This may be attributed to the fact that a portion of the surfactant is taking part of the interface between dispersed and continuous phase. Finally, although RT21HC–emulsions exhibited contact angles considerably inferior than those of distilled water, PCME sessile droplets did not rapidly spread as it happened for water+SDS with similar surfactant contents or for bulk–RT21HC.

Keywords: RT21HC paraffin; water; phase change material nano–emulsion (PCME); dynamic viscosity; surface tension; wetting behavior (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

Downloads: (external link)
https://www.mdpi.com/1996-1073/12/17/3334/pdf (application/pdf)
https://www.mdpi.com/1996-1073/12/17/3334/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:12:y:2019:i:17:p:3334-:d:262144

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().