1. 1 GDR CNRS AMC2 October 20-22, Sète ZIANE Nadia Supervisors: J. Leng and JB. Salmon

2.  Dialysis process:  Perfect control of the environment  Concentration of non-volatile solutes in aqueous solutions  Towards phase diagrams  Microfluidics interests:  Linear geometry  Easy observations of confined volume  Easy analysis and fast experiments 2

3. 3 PDMS PDMS membrane e = 30 – 40 µm glass slide rectangular channel w = 50 – 60 µm h = 30 – 40 µm L 0 = 1,5 – 3 cm L0L0 h nL Randall and al., 2005 Salmon and Leng, 2010

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5. 5 Step 1 Fill dead-end microchannels Step 3 Evaporation of confined droplets Step 2 Injection of a fluorinated oil or air L 0 = 1,5-3 cm 60 µm Noblin and al., 2008

6. 6 Continuous and uniform concentration   (t) =  0 L 0 /L(t) Evaporation rate controlled by activity  Hypotheses: No initial gradients P e = hV/D < 1  no vertical gradients Pervaporation rate uniform along x Quasi steady regime for water pervaporation

7. 7 Bleu brillant FCF at 0,1 mM (10x)  No gradients for molecular solutions 200 µm

8. 8 Fluorescent latex (40x)  Gradients at x=0 : evidence of « leakage » velocity Diameter = 20 nm J. Angly and al., 2012 x=0x=Lg 50 µm

9. 9  Gradients at x=0 : evidence of « leakage » velocity  Gradients at x=Lg : is not true Fluorescent latex (40x) Diameter = 200 nm h T D = h²/DT = h/V x=0x=Lg 50 µm

10. 10 Time ~ 1h30 Image analysis

11. 11  Accurate estimation of humidy using 1D model V f ~ 0,52 µm/s T e ~ 1500 s

12. 12 Water/glycerol 2% v/v Room humidity = 60% h = 26 µm, time ~ 2 hr Ninni and al., 2000

13. 13 Te ~ 2200 s

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16.  Robust measurements of the activity of aqueous solutions at the nanoliter scale  New chip design 16

17. 17 Estimation of liquid-liquid transition of ternary system PEG/water/ammonium sulfate PEG: 5% w/w Ammonium sulfate: 5% w/w Time ~ 1h20

18. 18  Development and characterization of new microfluidic devices including dialysis membranes  Control of osmotic exchanges at a nanoliter scale  Quantitative measurements of thermodynamic properties of complex fluids Microdialysis process Hsieh, 2007 Jensen and al., 2008

19. Questions ? 19