Doctoral position - 2015-2018
Laboratory : MADIREL – UMR-CNRS 7246
Group:
Interfaces entre phases condensées et transport
Location :
141, Traverse Charles SUSINI - 13397 – MARSEILLE - France
Contact:
Mickaël ANTONI
Tel :
33 (0)4 13 55 18 19
E-mail:
[email protected]
Website :
madirel.univ-amu.fr
Keywords: Evaporation; FTIR spectrometry; thermography; nanofluids
Deadline for application : April 27th
Thesis topic : Analysis by infrared spectroscopy of the evaporation kinetics of colloidal fluids.
The interaction between a droplet and its surrounding gas phase still remains in many aspects an
open question. This interaction involves complex mechanisms ranging from molecular phenomena to
hydrodynamic flows and requires a precise description of the condensed phases (colloid droplets and
substrates on which they are deposited) and the surrounding vapor phase [1,2]. The understanding of the
interplay between all these phenomena is key since they determine the overall evaporation kinetics.
Besides the interest of this doctoral proposition for fundamental purposes, another important
motivation here is the variety of industrial applications involving evaporative phenomena. They're
indeed extensively used in paintings, printing devices, in the development of new materials or
innovative techniques in nuclear decontamination.
The study of the evaporation of droplets is a research topic of MADIREL for many years. After
the development of models and computational fluid dynamics codes, the activity turned to experiments
and, recently, to spectral analysis. Complementary spectral diagnostics have been implemented for the
analysis of the droplets [3-5]. They are carried out simultaneously and allow precise analysis in both the
visible (optical microscope) and IR spectra (infrared camera and infrared spectrometer based on a FPA
matrix).
This thesis aims to use these diagnostics to describe evaporation kinetics of sessile droplets. The
liquids to be investigated will consist in simple fluids (water, ethanol, etc.), mixtures of simple fluids or
complex fluids (emulsions, suspensions of surfactant modified nanoparticles, etc). Metallic and
composite substrates will be studied. The selected candidate will prepare substrates and colloidal
solutions and will carry out the experiments. (S)he will process the data and analyze images. This
doctoral position requires knowledge of infrared spectrometry, an interest in material science and an
understanding of the physico-chemical phenomena taking place at liquid/gaz/solid interfaces. An
experience in the use of image processing tools (Image J, Gnuplot, Matlab) would be appreciated.
[1] Girard F., Antoni M. and Sefiane K., “INFRA-RED Thermography Investigation of an Evaporating Sessile Water Droplet
on Heated Substrates”, Langmuir (2010), 26(7), 4576-4580
[2] Sefiane, K., Shanahan, M. E.R. , Antoni, M., “Wetting and phase change: Opportunities and challenges”, Current opinion
in colloid and interface science, (2011), 16(4), 317-325
[3] Girard, F., Antoni, M., Faure, S., Steinchen, A., “Evaporation and Marangoni driven convection in small heated water
droplets”, Langmuir (2006) 22(26) 11085
[4] Girard F., Antoni M. and Sefiane K., “On the effect of Marangoni flow on evaporation rates of heated water drops”,
Langmuir (2008), 24(17), 9207-9210
[5] Girard F., Antoni M., Faure S. and Steinchen A., “Influence of heating temperature and relative humidity in the
evaporation of pinned droplets” Colloids and Surfaces A (2008), 323(1-3), 36-49