Simultaneous conductivity and viscosity in situ measurement technique (Systemic Rheology) Application to the study of the dynamic transitional

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2 Simultaneous conductivity and viscosity in situ measurement technique (Systemic Rheology) Application to the study of the dynamic transitional inversion Application to the study of the dynamic catastrophic inversion Development of a method for producing w/o/w multiple emulsions with a «2 steps-mono batch» process Development of a method for producing w/o/w multiple emulsions with a «1 step» process Concluding remarks

3 SYSTEMIC RHEOLOGY RHEOLOGY CHEMICAL ENGINEERING Stirred vessel (batch or semi-batch) equipped with a close-clearance impeller (complex viscous fluids) RHEOMETER A. Aït-Kadi, Ph. Marchal, A.S. Chrissemant, M. Bousmina and L. Choplin, Can.J.Chem.Eng., 80, (2002)

4 SPECIFIC ADVANTAGES of RHEO-REACTORS «Absolute» rheological characterization (Steady and unsteady flow, Mechanical spectroscopy) Mixing (Power consumption, Mixing time, Dispersion, Emulsification, ) Chemical or physical processes in batch or semi-batch modes (In situ rheological follow-up, Kinetics in controlled mixing conditions, «Rheological» stability, ) Formulation protocols (Additives incorporation procedures and sequences, )

5 VISCOSITY and CONDUCTIVITY in situ FOLLOW-UP in a RHEO-EMULSIFYER Process geometry (Anchor) Dispersing device (UT) conductivity detector Rotating vessel viscosity κ Thermostatic bath

6 Simultaneous conductivity and viscosity in situ measurement technique (Systemic Rheology) Application to the study of the dynamic transitional inversion Application to the study of the dynamic catastrophic inversion Development of a method for producing w/o/w multiple emulsions with a «2 steps-mono batch» process Development of a method for producing w/o/w multiple emulsions with a «1 step» process Concluding remarks

7 Temperature Change Method or Phase Inversion Temperature (PIT) method is facilitated with a temperature-sensitive surfactant system Mechanisms involved Morphological changes? Temperature (HLD) W/O Temperature decrease (nonionic) HLD=0 O/W W/O emulsion MOW O/W miniemulsion

8 Temperature (HLD) W/O O/W HLD=0 Microemulsion O tween85 W Three-Phase behavior (called Winsor III) = Bicontinuous Microemulsion

9 Viscosity torque Conductivity cell Oil phase : kerosene + 2%vol. isopropanol Thermostatic bath Water phase : water + 1g/100ml NaCl Surfactant : Sorbitan trioleate (Tween 85, HLB=11) 4.5g/100ml total vol. Vessel γ& eff = Optical microscopy Cooling rate: 0.05 C/s [ 50 C 10 C]

10 Viscosity Conductivity Miniemulsion W/O 31 C Maximum in viscosity Minimum in drop size Frontier between the W/O-A+ and the bicontinuous (WIII) microemulsion zone

11 Viscosity Conductivity 29 C Miniemulsion W/O Instantaneous dispersion into oil 29 C 31 C Non-zero conductivity presence of some bicontinuous microemulsion

12 Viscosity Conductivity 27 C 25 C «Complex mixture» : Miniemulsion O/W + emulsion w/o/m 23 C Miniemulsion W/O 23 C PIT~27 C At 23 C, 8%vol. inner water At 27 C, 86%vol. inner water Dispersibility experiments No instant. dispersion in water nor in oil Ext. Phase = Microemulsion (M)

13 Viscosity Conductivity Final drop size distrib. d ( 0.5) = 0.63µm 17 C Miniemulsion W/O Miniemulsion O/W + emulsion w/o/m Miniemulsion O/W [ 20 C 17 C], T µ drop size increases Instantaneous dispersion into water 20 C

14 viscosity conductivity f f W W = = f f W W = =

15 Simultaneous conductivity and viscosity in situ measurement technique (Systemic Rheology) Application to the study of the dynamic transitional inversion Application to the study of the dynamic catastrophic inversion Development of a method for producing w/o/w multiple emulsions with a «2 steps-mono batch» process Development of a method for producing w/o/w multiple emulsions with a «1 step» process Concluding remarks

16 Increase in oil content FORMULATION as HLD B + - B o/w/o W/O + A inversion line w/o/w C + A - C - O/W Oil COMPOSITION Water Increase in water content

17 Stirring or Macromixing time increase in mechanical energy E P t mechan M W/O Power/u.vol. An increase in E mech at constant HLD results in delaying the catastrophic inversion with time O/W

18 W/O w/o/w O/W Time t M

19 Viscosity torque torque Ultra-Turrax Conductivity cell Oil phase : kerosene + 2%vol. isopropanol Thermostatic bath Water phase : water + 1g/100ml NaCl Surfactant : Sorbitan monolaurate (Span 80, HLB=4.3) Igepal CO-630 (N9, HLB=13) 7g/100ml total vol. Vessel γ& eff = Optical microscopy Cooling rate: 0.05 C/s [ 50 C 10 C]

20 Anchor (200 s -1 ) Anchor (200 s -1 ) + UT (9000 rpm) Anchor (200 s -1 ) + UT (13000 rpm) Viscosity (Pa.s) Conductivity (ms/cm) w/o/w time (s)

21 Simultaneous conductivity and viscosity in situ measurement technique (Systemic Rheology) Application to the study of the dynamic transitional inversion Application to the study of the dynamic catastrophic inversion Development of a method for producing w/o/w multiple emulsions with a «2 steps-mono batch» process Development of a method for producing w/o/w multiple emulsions with a «1 step» process Concluding remarks

22 Production of w/o/w multiple emulsions with a «2 steps mono batch» process MODEL SYSTEM Oil phase : kerosene +2-butanol (2%vol.tot.) + Tween 85 (HLB=11, 3% tot.vol.) Water phase : water + NaCl (1%w/tot.vol.) Surfactant for stabilising the primary emulsion : PGPR (HLB=4.3) Surfactant in oil phase (2nd step) : Tween 20 (HLB=16.7, 3%w/tot.vol.) 1 2 PRINCIPLE Elaboration of a primary mini-emulsion in the oil phase with the help of a moderate mechanical energy supply, following a specific route on the formulation composition map Elaboration of the multiple emulsion in the same vessel after modifying the position of the macromixing tool in the lower water phase, in which an appropriate surfactant was added

23 STEP 1 Production of w/o/w multiple emulsions with a «2 steps mono batch» process

24 STEP 1 Production of w/o/w multiple emulsions with a «2 steps mono batch» process Mini-emulsion d(0.5) = 0.3 µm

25 Production of w/o/w multiple emulsions with a «2 steps mono batch» process STEP 2 3% (p/v total ) Tween20 (HLB=16.7) T=25 C s -1 sur 200 s

26 Production of w/o/w multiple emulsions with a «2 steps mono batch» process STEP 2 d(0.5) = 13 µm d(0.5)=13 µm

27 Simultaneous conductivity and viscosity in situ measurement technique (Systemic Rheology) Application to the study of the dynamic transitional inversion Application to the study of the dynamic catastrophic inversion Development of a method for producing w/o/w multiple emulsions with a «2 steps-mono batch» process Development of a method for producing w/o/w multiple emulsions with a «1 step» process Concluding remarks

28 Elaboration of w/o/w multiple emulsions with a «1 step» process PRINCIPLE

29 Elaboration of w/o/w multiple emulsions with a «1 step» process The emulsification in the C+ zone can be facilitated (we increase the size of this zone) supplying a higher mechanical energy or increasing the oil phase viscosity (red arrows). W/O The control of these parameters is however fundamental in order to avoid the catastrophic inversion. O/W

30 W/O w/o/w O/W Time t M

31 Injection stabiliser Specified E mech Selected conductivity

32 Elaboration of w/o/w multiple emulsions with a «1 step» process

33 Simultaneous conductivity and viscosity in situ measurement technique (Systemic Rheology) Application to the study of the dynamic transitional inversion Application to the study of the dynamic catastrophic inversion Development of a method for producing w/o/w multiple emulsions with a «2 steps-mono batch» process Development of a method for producing w/o/w multiple emulsions with a «1 step» process Concluding remarks

34 Development of a simultaneous in situ conductivity and viscosity follow-up technique for studying : Dynamic transitional inversion in emulsion Dynamic catastrophic inversion in emulsion mechanisms & morphologies Multiple emulsions preparation methodologies: 2 steps one batch 1 step with controlled internal phase content