Cone–Plate Rheometer as Reactor and Viscosity Probe for the

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Cone-plate rheometer as reactor and viscosity probe for the detection of transitional phase inversion of Brij30-Isopropyl myristate-Water model emulsion. Christel Pierlot, Jesús Fermin Ontiveros, Marianne Catté, Jean-Louis Salager, and Jean Marie Aubry Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.6b00399 • Publication Date (Web): 21 Mar 2016 Downloaded from http://pubs.acs.org on March 22, 2016

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Industrial & Engineering Chemistry Research

Cone-plate rheometer as reactor and viscosity probe for the detection of transitional phase inversion of Brij30-Isopropyl myristate-Water model emulsion. Christel Pierlot*,1, Jesus F. Ontiveros1, Marianne Catté 1, Jean-Louis Salager2, Jean-Marie Aubry1 1 2

Univ. Lille, ENSCL, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France Laboratorio FIRP, Ingeniería Química, Universidad de Los Andes, Mérida 5101, Venezuela

Abstract Brij30/Isopropyl myristate/Water model emulsions were used to study the inversion morphology change from O/W to W/O. The transitional phase inversion was detected by monitoring the electrical conductivity during a heating-cooling cycle while the viscosity of the emulsion was followed under constant shear rate with a cone-plate rheometer equipment. The two methods provide similar values of phase inversion temperature. However different rheological profiles are observed depending on the surfactant concentration and water fraction. Viscosity maps of formulation-composition maps (specifically Temperature-Surfactant concentration and Temperature-Water Fraction) pointed the occurrence of both transitional and catastrophic inversion processes. A complete formulationcomposition map with all different emulsion morphologies and iso-viscosities contours for the 9% Brij30/IPM/Water is presented. The use of a commercial cone-plate rheometer exhibits several advantages over the classical conductivity measurement; in particular it does not imply any electrolyte addition in the aqueous phase and requires only a small volume of emulsion.

1. Introduction 1.1. General background About one century ago, Bancroft1,2 suggested that the emulsion type, that is, oil-in-water (O/W) or water-in-oil (W/O), mainly results from the preferential solubility of the surfactant in the water or oil phase, respectively. In 1949, Griffin introduced the concept of HLB (Hydrophilic Lipophilic Balance)3 as an arbitrary numerical scale describing the more or less hydrophilic nature of a surfactant, associated with (O/W) or (W/O) emulsions respectively. For polyethoxylated nonionic surfactant systems, an increase in temperature tends to trim down the interactions between the polyether chain and the water molecules. Consequently, it turns the surfactant less hydrophilic, and typically triggers the emulsion inversion from O/W to W/O morphology at the so-called phase inversion temperature (PIT).4 The opposite inversion from W/O to O/W takes place upon cooling at

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or close to the PIT. Such emulsion inversion is driven by a phase behavior transition and as a result often produces emulsions with fine droplets at a low energy expense even with viscous phases, according to what has been called the PIT emulsification-method5 and has been used for decades for such purpose.6

In the 1970s, numerical relationships including the effects of several formulation variables were established, in relation to the research efforts to attain ultra-low interfacial tensions in Surfactant/Oil/Water (SOW) microemulsions systems necessary for enhanced oil recovery.7 A linear contribution of each variable was found in the equation determining the occurrence of the optimal formulation, with minimum interfacial tension.8,9 The effects of all intensive variables were gathered twenty years later in a similar generalized formulation variable correlation called Hydrophilic Lipophilic Deviation (HLD) which is the dimensionless expression of the difference of affinity of the surfactant for the water and oil phases.10 The equilibrium phase behavior and the emulsion morphology resulting from stirring of a preequilibrated system were found to be directly linked11, and the particular conditions called optimum formulation (HLD = 0) essentially correspond to the boundary between O/W and W/O emulsions. This coincidence is not necessarily valid for non-equilibrated surfactant-oil-water systems for which complex delays or hysteresis phenomena can take place.12,13 As a consequence it is recommendable to carry out inversion experiments with systems close to equilibrium, a condition which in general is quickly reached with formulation close to optimum formulation. In practice, it is thus important to monitor morphology changes taking place close to or at the inversion induced by temperature effect or by water addition, and these are the used techniques to control the manufacture of nutrient emulsions for fermentation processes, epoxy or polyurethane waterborne paints or silicone putties. Any method able to detect drop size, electric properties or viscosity change is likely to be a candidate to monitor the phase inversion, and to pinpoint it with accuracy. The classical way to detect emulsion inversion consists in measuring the conductivity of the emulsion. Conductivity is typically high for the O/W morphology and low for the W/O one, especially if the aqueous phase contains some electrolytes as often the case in practice. The conductivity of O/W emulsions have been modeled.14 Equations have been established for the determination of the electrical conductivity on dispersions of three-phase emulsions, from volume fractions of each dispersed phase.15 Electric properties of emulsions under sinusoidal constraints have been studied and the phase inversion was detected from the measurement of the slope in the

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real part of impedance at low frequencies by the use of parameters such as double layer capacitance and charge transfer resistance.16,17,18,19 However, the conductimetry method has some drawbacks. First, to get a clear-cut detection of the inversion, it requires the aqueous phase to be conductive, i.e. to contain some electrolytes. Secondly, the variation of conductivity likely to indicate some morphology change prior to inversion, only supplies information in the O/W→W/O direction of change, i.e. on the eventuality of multiple w/O/W morphology. But it is essentially ineffective to detect multiple emulsions of the o/W/O type. Finally, the conductivity does not give any valuable information about drop size, which is often an important issue in practical cases. Moreover, if the solution is too viscous it is not possible to take conductivity measurement. Light backscattering20,21 has been tested with C10E4-Octane-Water system. It is a complementary technique to conductivity measurement to track emulsion phase inversion, it may be an easy to use, non-invasive and accurate method, provided that experimental conditions has been optimized. Recently, Near-Infrared spectroscopy (NIR)22 has been used to study an Ethoxylated nonylphenol/Heptane-Toluene/Water system. Difference in sizes and number of droplets and differences in emulsion morphologies, including multiple morphology types, change the NIR light extinction during inversion23.

The PIT of liquid paraffin and isopropyl myristate with Tween80, Span60, Brij92 and 96 systems were also determined17 by monitoring continuously the apparent viscosity versus temperature at a constant shear rate. These shear stress-temperature studies were performed using a Haake RV 12 rotational viscometer with coaxial-cylinder measuring device. However due to the relatively great quantity (more than 10 mL) of emulsion to be analysed and to avoid delay and hysteresis phenomena conditions close to equilibrium are required. In practice the gradient of temperature has to be low, and thus experiments are time consuming. Lehnert et al.17 also showed that the PIT can be evaluated by performing usual shear stress versus shear rate curves at given temperature. In the case of a positive thixotropy, the temperature is below the PIT and vice versa. However, this method has not been validated for another system, and does not determine the PIT accurately. Allouche et al.24 demonstrated that coupling a torque sensor to a stirrer is useful to detect phase inversion and obtain rheological information simultaneously. Regarding the transitional phase inversion, continuously monitoring of both conductivity and viscosity of emulsion (Tween85/2-propanol/ kerosene/water) enables the identification of several phenomena which take place during the process. To extract “absolute” viscosity-shear rate data similar to what is attained in a conventional geometry rheometer 3



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inside this “rheomixer” reactor, a Couette analogy has been applied binding shear stress to the torque value and shear rate to the speed of the impeller.24 Anisa et al.25 examined the effect of three types of crude oils emulsified with Span 83 on the phase inversion temperature using a Brookfield rotational digital rheometer, however viscosity could not be measured for all temperatures and the rheometer was thoroughly cleaned between measurements of different samples.

In the present article a cone-plate rheometer is used both as the inversion vessel reactor and as a rheology measurement device with a very small amount of fluid (2 mL). Such an apparatus insures a uniform velocity gradient everywhere in the sample at constant temperature and a precise viscosity estimate. The phase inversion temperature of Polyoxyethylene(4) dodecylether (Brij30)/Isopropyl myristate (IPM)/Water emulsified systems at different water/IPM ratios is deduced from the rheological profile. The iso-viscosity contours are then plotted on bidimensional formulation (temperature) - composition (water fraction/surfactant) maps and the abrupt changes on viscosity allows to precisely placing the borders between multiple emulsions and single emulsions.

2. Experimental 2.1. Materials Technical grade polyoxyethylene lauryl ether with an average of 5 ethylene oxide group per molecule was supplied by Sigma–Aldrich as Brij30 (indicated as Tech-C12E4). Isopropyl myristate (IPM) was purchased from Cooper. Sodium chloride NaCl (purity ≥ 99.5%) was obtained from Acros Organics. Demineralized water (conductivity 1.34 S.cm-1 at 21 °C) was used in the aqueous phase. 2.2. Conductivity experiments The surfactant/oil/water system was prepared 24 h before the emulsion experiment by pouring in an erlenmeyer flask a volume of water, a volume of isopropyl myristate, and then an aliquot of Brij30. The amount of Brij30 was adjusted so that the final proportion of surfactant is x wt.% of the whole system, whose volume is 10 mL. The water weight fraction fw is calculated by Eq. (1). fw = mw / (mw + mO) (1) Where mW and mO are the weights of water and oil respectively. The prepared system was slowly hand-shaken during a few seconds and left to pre-equilibrate at room temperature (25 ± 2 °C) overnight. This technique is known to warrant that the attained emulsion upon stirring is the same than the one reached from an equilibrated system particularly when the formulation is close to optimum.21, 12

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Before starting the experiment, the formed emulsion was kept at initial temperature for 15 min, being continuously stirrred with a magnetic stirrer at 700 rpm. A gradient of temperature (1 °C.min-1) was then applied. The temperature was controlled by a cc3 Huber Ministat bath. The conductivity and temperature are measured by a Radiometer Analytical CDM 210 conductimeter fitted with a CDC741T platinized platinum probe. The conductimeter and temperature signals are sent to a data acquisition system. The software used was custom written in the Labview 7.1 National Instruments platform software. 2.3. Rheological experiments After conductivity experiments, emulsion was kept at the initial temperature 10 or 20 °C for 15 min and then homogenized with ultraturrax IKA during 30 seconds at 11500 rpm. A 2 mL sample was then placed in the gap of a cone-plate (6 cm, 2°) Kinexus rheometer (Malvern). A heating/cooling rate of 1°C.min-1 was then applied at a continuous shear rate of 500 s-1. 2.4. Construction of fish diagrams of Brij30- Isopropyl myristate –Water (NaCl(aq) 10-2M) 1 g samples were prepared in 2 mL vials by weighing successively water (W), oil (O, Isopropyl myristate) and surfactant (S, Brij30). In all samples, the water weight fraction fw equals 0.5. The surfactant/oil/water system was then gently mixed to assist the contact of phases while avoiding emulsification. The vials were then placed in a thermostatic bath HUBER Ministat 125 at the required temperature T (± 0.1 °C) until phase separation and equilibrium were reached, which took at least several days, and up to more than one week in the vicinity of transition zones. Visual inspection of the vials allowed the determination of the phase behavior in order to classify them according to the Winsor nomenclature.26

3. Results and discussion In order to choose suitable physicochemical conditions to validate the use of a rheometer and to compare results obtained from emulsified and equilibrated systems, the phase behavior of Brij30/IPM/10-2M NaCl(aq) system at fw = 0.5 is analyzed. Conductivity and viscosity profiles at different temperatures are plotted at 9% Brij30 (for different fw) and at fw = 0.5 (for different % Brij30). The value of phase inversion temperature (PIT) by the two methods is similar. The influence of concentration of surfactant and water fraction is then investigated, pointing out the different shapes of viscosity-temperature profiles. Finally, iso-viscosity diagrams are presented in both Temperature-Surfactant concentration and Temperature-Water fraction diagrams. 3.1. Fish diagram of Brij30- Isopropyl myristate –Water (NaCl(aq) 10-2M)

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The ‘‘Fish’’ diagram27 at equal weight ratio of oil and water (fw = 0.5) of Brij30/IPM/10-2M NaCl(aq) temperature systems is presented in figure 1. This representation is useful to determine the so-called optimal formulation at a given water fraction and also gives access to characteristic points that define the system. The “Fish tail” or X point is defined by the temperature T* (40.2 °C) and the minimum surfactant concentration C* (13.1%) at which aqueous and oily excess phases vanish and a single microemulsion phase is observed, indicating the transition from WIII to WIV phase behavior. This X point is an important information for a given surfactant/oil/water system because it may be used to compare surfactants or oils. The “fish head”, i.e. the minimum surfactant concentration at which a three phase behavior appears (WIII zone) is noted as C0 (7.0%). The isopropyl myristate presents an equivalent alkane carbon number of 7.328,29, however the value of C0 is higher than for the corresponding alkane, i.e. heptane or octane. The polarity of the ester increases the monomeric solubility of surfactant in the oil phase and higher concentrations of polyethoxylated surfactants are required to generate a microemulsion. 80 Tu

Winsor I Winsor III

70

Winsor II Winsor IV

Temperature (°C)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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60

PITRheo

50 T* 40

30 C*

C0 20 0

5

10

15

20

25

Surfactant (%)

Figure 1. Fish plot at fw = 0.5 for the Brij30/IPM/10-2M NaCl(aq) system (Winsor I : ■; II : ▲ ; III : □ ; IV : ◊). The phase inversion temperature determined by rheology (PITRheo) has also been plotted (●).

The shape of this fish diagram exhibits a strong asymmetry. As it has been known for a long time, this is due to the fact that the optimum formulation of systems based on oligomeric surfactant such as 6


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Brij30 varies depending on the surfactant concentration30 and on the water/oil ratio.31 A simple model for selective partitioning of ethoxylated oligomers between water and oil has been proposed32 and explained in detail elsewhere.33 An increase of surfactant concentration tends to decrease the selective partitioning of less hydrophilic (low EON oligomers) species to the oil phase, thus the remaining oligomer mixture at interface becomes more lipophilic and thus a lower dehydration of the EO group is required to attain optimum formulation. As a consequence the PIT is expected to take place at a lower temperature for higher concentrations of Brij30. The system required a very long time to equilibrate as already observed for nonionic technical alkyl polyethoxylated surfactants. This behavior is attributed to the slow kinetics of the formation and destruction of liquid crystals.34 3.2. Validation of the rheological method to determine the PIT. Figure 2 presents the variation of specific conductivity and apparent viscosity with temperature for the 9% Brij30/IPM/10-2M NaCl(aq) system, near the center of three phase area of the fish diagram, from 44 °C to 62 °C. The specific conductivity decreases sharply from a very high value to a low one within a temperature range of a few degrees, the specific conductivity defining the PIT (PITCond) is chosen as the temperature at which the specific conductivity of the emulsion is half of the maximum PIT value (on an arithmetic scale). Some authors21, proposed to repeat the same procedure to generate a second and third cycles, with some differences if the temperature variation is relatively rapid35. In our experimental conditions, preliminary trials have showed that if the temperature change is set to a “slow” rate of 1°C/min (up and down) only a small hysteresis phenomenon is exhibited (53.0 °C and 53.5 °C for PIT during heating and cooling respectively in figure 2). The specific conductivity variation indicates a particularly narrow inversion range, hence a more accurate PIT determination. Second heating/cooling cycle exhibits the same shape and results are analogous to the first one. For the sake of clarity, only 1 cycle is shown in figure 2.

For viscosity experiments, preliminary trials have indicated that the most reproducible data were obtained when the shear rate is 500 s-1 in both heating/cooling cycles. A shear rate larger than 900 s-1 could have produced a centrifugal loss of the sample, whereas a shear rate significantly lower that 500 s-1 was insufficient to keep and regenerate the emulsion when passing through the PIT zone where the drops are known to coalesce very quickly. In order to make sure that the emulsion is kept and reform when temperature is close to the PITCond the sample was submitted to one cycle starting with a heating ramp from 45 to 60 °C followed with a cooling ramp from 60 to 45 °C (figure 2). The 7



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heating-cooling sequence has been preferred to the opposite to avoid the sample staying at a higher temperature, because it could favor water evaporation.

Figure 2. Specific conductivity and viscosity versus temperature at 1°C.min-1 (heating-cooling) for 9% Brij30/IPM/10-2M NaCl(aq) system. Stirring rate at 700 rpm and shear rate at 500 s-1 for specific conductivity and rheology experiments respectively.

Close to the so-called “optimal formulation”, where the interfacial tension between oil and water phases presents a minimum value, a minimum of viscosity has equally been reported a long time ago regardless of the studied formulation variable36. During the cycle (heating-cooling) shown in figure 2, it can be seen that there is a minimum of viscosity (3-4 mPa.s for 53.7 °C) located close to PITCond. Thus it is clear that the selected experimental conditions, particularly the shear rate produced by the rheometer cone-plate device, ensure the reversibility of emulsion inversion and the accurate determination of the inversion. PIT determined from viscosity profile of emulsion matches very well with the classical specific conductivity method. Consequently the temperature at the minimum viscosity will be called PITRheo and it will be determined on the first heating ramp in rheology curves. 3.3. Effect of Brij30 concentration on specific conductivity and viscosity curves versus temperature 8


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1 200

A

Conductuvity (µ µS.cm-1)

1 000 6% Brij30 800

9% 600

12% 15%

400

18% 21%

200

0 10

20

30

40 50 Temperature (°C)

60

70

80

1

B 21% Brij30

18% 0.1

Viscosity (Pa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


15% 12% 6%

0.01

9%

0.001 10

20

30


60

70

80

Figure 3. Temperature-dependence of the specific conductivity (A) and of the viscosity (B) of the emulsion formed with Brij30/IPM/10-2M NaCl(aq) at different Brij30 concentrations. Ramp of temperature at 1 °C.min-1 and 500 s-1 for the shear rate.

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Figure 3A presents the evolution of the specific conductivity for different Brij30 weight ratios. The phase inversion occurs as expected for 9, 12, 15, 18 and 21% of Brij30 but not for 6%. This is because the latter concentration (6%) is lower than C0 (7.0%) as shown on the fish diagram (Figure 1). The fish diagram obviously induces a limitation in the correspondence between micro and macro-emulsions types. Pizzino et al.37 highlight the difficulty of inversing a C10E4/Octane/Water system even for concentrations slightly higher than C0 under certain agitation conditions, and temperature gradient. For the case of a very high concentration (21%) of Brij30 it has been difficult to detect the phase inversion by specific conductivity, and the curve presented in figure 3A is the result of several assays.

Figure 3B presents the viscosity variations at different weight concentrations of Brij30. The expected minimum of viscosity36 is clearly observed for all concentrations higher than C0 except for the experiment at 21% of Brij30 which is in the fish tail where liquid crystals are expected. Since emulsion viscosity strongly depends on surfactant concentration, it is plotted in a log scale, which by the way does not change the accuracy in determining the location of the minimum, indicated as PITRheo. Under the fixed experimental conditions for specific conductivity and viscosity measurement, the method is clearly less adequate at high concentrations of surfactant by the increase of viscosity and probably by the presence of liquid crystals, as suggested by the appearance of a secondary maximum on specific conductivity profiles for 15,18 and 21% Brij 30.38

Table 1 shows the PIT obtained from the specific conductivity and viscosity events at different surfactant concentrations. These data clearly indicate that both specific conductivity and rheological methods give consistent PIT values in this range of surfactant concentrations from C0 to 18% Brij30. Table 1. PIT values detected by specific conductivity (PITCond) and by rheology (PITRheo) Brij30/IPM/10-2M NaCl(aq) systems with different Brij30 concentrations (9, 12, 15 and 18 wt.%). Brij30 (wt.%) 9

12

15

18

PITCond (°C)

53.0

46.0

40.2

33.0

PITRheo (°C)

53.5

44.0

38.9

35.1

3.4. Effect of fw on specific conductivity and viscosity curves versus temperature It has been shown in a few publications39,40 that the fish shape aspect, particularly its tilting, depends on the water fraction fw of the system. This has been explained a long time ago, reporting that the optimum formulation of systems containing mixtures of surfactants can be altered by the total 10


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surfactant concentration30 and the water/oil ratio31 through a change in the partition coefficient of the different species between bulk phases and interface. This is also the case of commercial ethoxylated surfactants that are mixture of oligomers often exhibiting a wide range of ethoxylation degrees.32 It is thus expected that a modification of fw is likely to produce an alteration of the interfacial formulation, and as a consequence, a change in inversion position. Figure 4A presents the specific conductivity variation during an increase in temperature at different fw. Under our experimental conditions the phase inversion is found to take place from fw = 0.4 to 0.8. For fw = 0.3 and 0.9 no inversion is detected on specific conductivity profiles. Indeed, for fw = 0.9, the viscosity profile does not present a minimum at a specific temperature but a low viscosity constant zone (between 30 and 38 °C, the viscosity remains constant at 5 mPa.s. This profile is not included in figure 4B for sake of clarity).

Figure 4B shows the variation of viscosity during heating from 20 °C to 80 °C for different fw. All viscosity profiles shown in figure 4B exhibit a minimum viscosity corresponding to the PITRheo. It is worth noting that the viscosity minimum (ηPIT Rheo) slightly increases with fw up to fw=0.7 (Table 2). It may be stated that the PIT values determined from rheology and specific conductivity curves (Table 2) are thus very close, with a maximum difference of 1.5 °C, which is essentially compatible with an accuracy of about 1 °C reported for specific conductivity PIT values.

Table 2. PIT values detected by specific conductivity (PITCond) and by rheology (PITRheo) for 9% Brij30/IPM/10-2M NaCl(aq) systems with different fw. fw 0.3

0.4

0.5

0.6

0.7

0.8

PITCond (°C)

n.d.

58.9

53.5

48.6

41.1

n.d.

PITRheo (°C)

75.2

60.7

53.1

47.9

41.3

32.0

ηPIT Rheo (mPa.s)

1.8

2.8

3.9

5.0

6.6

5.1

11



1000

A

0.7 900

0.6

0.5

800

0.4

Conductivity (µS.cm-1)

700 600

0.3

500 400

0.8

300 200

fw = 0.9

100 0 10

0.1

20

30


60

70

80

fw=0.3

B

0.4 0.5 0.6

0.01

0.3

0.4

0.5

0.8

0.8

0.6

0.7

0.7

Viscosity (Pa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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0.001 10

20

30


60

70

80

Figure 4. Temperature-dependance of the specific conductivity (A) and of the viscosity (B) of the emulsion formed with 9% Brij30/IPM/10-2M NaCl(aq) at different fw. Ramp of temperature: 1 °C.min-1. Shear rate: 500 s-1.

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3.5. Water fraction (fw) effect on viscosity profiles. Looking at figures 3B and 4B it is worth noting that the viscosity minimum profile near the PIT changes depending on the composition variable. Viscosity profile around PIT can be specified with four characteristic points noted Min1, Max1, PIT, Max2 in figure 5. The existence of two maximums in each viscosity profile is related to two minima on the droplet size that exist on each side of the optimal formulation as discussed elsewhere41, in the present case just before and after the PIT. Two profile types are observed for the studied system depending on the relative values of Max1 and Max2 on each side of the PIT. If viscosity at Max1 is higher than at Max2, an “A” profile is occurring. Otherwise, a “B” profile is observed. According to figure 3B and 4B, the profile type changes with fw and surfactant concentration as indicated in figure 5.

“A” Profile

fw = 0.6

fw > 0.6

“B” Profile

Max1

fw < 0.6

Max2

w/o

Min 1

Viscosity

o/w

o/w

w/o

w/o

o/w

PIT

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Temperature Figure 5. Schematic evolution of viscosity versus temperature with fw for 9% Brij30/IPM/10-2M NaCl(aq) showing the “A” and “B” characteristic profiles.

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1000

Viscosity (mPa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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100 Min1 Max1 PIT Max2

10

1 0.3

0.4

0.5

0.6 fw

0.7

0.8

0.9

Figure 6. Viscosity for Min1 (), Max1 (), PIT (), Max2 () versus fw for 9% Brij30/IPM/10-2M NaCl(aq) obtained from curves in figure 4B.

The evolutions of viscosity for Min1, Max1, PIT, Max2 with water fraction fw are shown on figure 6. Max1 is practically constant (15 mPa.s) with fw whereas Max2 is strongly increasing with fw. Equal values are found to occur at fw = 0.63. For this particular value, a symmetrical profile around PIT is reached. Taking into account the density ratio ρIPM/ρWater = 0,85 at 20°C, the mass fraction of water

fw = 0.63 corresponds to a volume fraction fΦ = 0.63x0.85 = 0.54. This actually means that the perfectly symmetrical viscosity (complex) profile around PIT is attained when the emulsion contain essentially the same volume of aqueous and organic phases. Figure 5 can explain why Allouche24 obtained only type “A” profiles with polyethoxylated sorbitan trioleate (Tween85)/Kerosene/Water system at low fw (≤ 0.5). Figure 3B shows that the transition “A” to “B” profile may also be obtained with a reduction in the concentration of Brij30 at constant

fw 0.5). Thus “B” profiles have been observed by Lehnert17 with polyethoxylated Brij mixture /liquid paraffin/water at fw = 0.5 for low Brij concentration (6%). Thus the viscosity of the o/w emulsion taken just before the PIT (around point Max1) can be either lower or higher than that of the w/o emulsion taken just after the PIT (around point Max2) depending on the fw and surfactant concentration.17 For both “A” and “B” profiles, as the temperature approaches the PIT from both sides, i.e. as the formulation tends to the so-called optimum, the interfacial tension decreases, inducing the formation of smaller droplets. However, the coalescence rate increases drastically at the approach of optimum formulation, in our case the PIT8,9,42,43,44,45,46 thus tending to produce larger drops. The two opposite

14


Page 15 of 37

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effects do not alter the drop size in the same way, but always result in a minimum drop size whose exact position on both sides slightly depends on some other factors such as the stirring energy as discussed elsewhere.39 It is not known how these minimum drop sizes obtained at Max1 and Max2 could be related to the “A” or “B” profile, and it is probably a very complex issue. It has been shown that the presence of liquid crystal, that can be observed by the bump in the specific conductivity curve near the PIT (for example see figure 2 between 54 and 58°C)37 is likely to perturb the formation of such small droplets39, and thus alter the profile. It is thus safer to state that this profile applies if the inversion takes place through a WIII phase behavior. Indeed, the shape of A and B profiles of viscosity can be modified by other composition variables such as surfactant concentration or also by the differences on viscosity between oily and aqueous phases.

3.6. Iso-viscosity curves Isoviscosity lines versus surfactant concentration and fw (Figure 7A and 7B) were drawn by connecting points having the same viscosity values obtained from figure 3B and 4B and from complementary experiments. The blue, green and red (dotted) lines correspond to low (< 8 mPa.s), medium (10 and 20 mPa.s) and high (≥ 50mPa.s) viscosity respectively. For example, experimental points for 10 mPa.s (black points), and the corresponding isoviscosity curves are presented in figure 7B. Characteristic points Min1, Max1, PITRheo and Max2 are equally connected and represented with their viscosity values.

The shape of the fish WIII phase behavior zone is the same as the lines connecting PITRheo points and its area is essentially limited by the Max1 and Max2 lines. Unfortunately, it is not possible, using rheological information in figure 7A to determine more precisely the shape of the Fish. The reason is probably that the rheological curves are obtained during relatively quick dynamic process whereas Winsor types have been obtained at the thermodynamic equilibrium after several days or weeks. This can be confirmed by the position of the measured PITRheo that is not exactly at the middle of the WIII fish body or at the center of the Winsor IV zone. The isoviscosity lines in temperature-fw plan (Figure 7B) are similar to those generally reported47 in the formulation-composition map. In principle a transitional inversion of the emulsion should occur in the central region of the formulation-composition map. This so-called transitional inversion frontier separates the O/W from the W/O emulsions. The transitional inversion takes place whatever the direction of change48. At both extremes of the formulation-composition map (at low water 15



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Page 16 of 37

fractions for HLD < 0 and at high water fractions for HLD > 0), the water fraction is the main variable to induce the so-called catastrophic inversion48. The branch for these zones are almost vertical lines, however several factors as the rate of water to oil ratio49,50 agitation speed51 or surfactant concentration50 can change the border producing the hysteresis of the inversion.52 This behavior is general for most SOW systems, and the temperature as formulation variable can be replaced by salinity, oil nature, surfactant hydrophilic-lipophilic balance. For example Miñana et al.53 presents such isoviscosity lines obtained with a double gap Couette cell, for the sodium dodecyl sulfate/kerosene/NaCl(aq) system in the Salinity-fw plan. In our case, the viscosity (and the specific conductivity) profiles of figure 4 allow to clearly establish the limit of the inversions. The transitional inversion (bold solid) line is drawn by connecting points (PITRheo, fw) obtained using figure 4B and additional data. The junction with the catastrophic inversion lines is estimated by dotted dashed lines. The abrupt changes in viscosity observed in in each side of vertical dotted lines with low (0.15) and high (0.95) fw can be used to infer the transition zone (catastrophic inversion). In our experimental conditions, the first catastrophic inversion (o/W/O to O/W) occurs at fw = 0.15 at temperatures between 10 and 65 °C whereas the second one (W/O to w/O/W) occurs at fw = 0.95 at temperature at temperature superior to 40 °C. It is clear that the isoviscosity lines near fw = 0.15 and 0.95 allowed an accurate drawing of vertical dashed lines corresponding to catastrophic inversion, between regions of low and high viscosity. This result generalizes over the whole temperature range the information shown only at 20 and 80 °C in Figure 8.

16


Page 17 of 37

80

A

2 2

70 6 4

60

8 10

10

Temperature (°C)

6 2

50

7

17

40

Fish

20

5

10 30

25

10

8

15

50

40

20

30 100

200

10

30

20

300 300

10 0

2

4

6

8

10

12 % TA

14

16

18

20

22

24

80 2

B

2 2

5

10

2

20

70 3

50 2.8

60 Temperature (°C)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


10

5

5 8

15

4

15

100

12

50 18

5

15

15

28 68 120

7

40 7.5

15

10 5

30

5 15

20

4

20 10

10 0

0.1

100 0.2

50 0.3

0.4

20 0.5

10 0.6

0.7

5 0.8

0.9

1

fw Figure 7. Isoviscosity curves (indicated in mPa·s) of Brij30/IPM/10-2M NaCl(aq) systems in the Temperature%TA (A) and Temperature-fw (B) plans obtained from figure 3A and 3B. Viscosity were measured at shear rate = 500 s-1 from 10 to 80 °C at 1 °C.min-1. Characteristic points Min1 (), Max1 (), PITRheo () and Max2 () as defined in figure 6 and Fish shape are represented. Viscosity values on dashed lines at 20 and 80 °C are 17



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Page 18 of 37

presented in figure 8.

3.7. Effect of fw on Viscosity at 20 and 80 °C for the 9% Brij30/IPM/Water system To highlight the change in viscosity during the two catastrophic inversions, figure 8 shows viscosity as a function of fw for 20 and 80 °C (dashed horizontal line in figure 7B). These temperatures were chosen in order to compare extreme conditions of lipophilic (80°C) or hydrophilic (20°C) behavior of the surfactant. Indeed, all values for PIT are lower than 80°C and higher than 20 °C and the morphology of emulsions is certainly O/W under than 20 °C and W/O above 80 °C. Figure 8 clearly shows this sharp increase in viscosity at 20°C during the change from fw = 0.1 to 0.2 where the viscosity can quickly increase from less than 10 mPa.s to more than 400 mPa.s at 20°C. The second catastrophic inversion occurs at fw = 0.95, whith a decrease of viscosity (20 to 1mPa.s) at 80 °C. The viscosity of an emulsion depends on many different factors (viscosity of external phase, internal phase fraction, droplets size and slightly of the internal phase viscosity)48 that have to be taken into account when interpreting the data. Thus, the inset on figure 8 presents the viscosity under 500 s-1 from 10 to 80°C, of IPM, IPM with 9% Brij30 (fw = 0.0), NaCl(aq) 10-2M and NaCl(aq) 10-2M with 9% Brij30 (fw = 1). The viscosity of IPM is 5.6·10-3 Pa.s at 20°C and 1.9·10-3 Pa.s at 80 °C. No difference is observed in the rheological profile between IPM and 9% Brij30 in IPM (fw = 0.0). Since Brij30 is not totally soluble in water, the obtained dispersion for 9% Brij 30 in water (fw = 1.0) shows a higher viscosity than the NaCl(aq) 10-2 M solution, particularly for temperatures lower than 45°C. Figure 8 shows that at 20°C and with fw < 0.15 the viscosity of the emulsion is low (6x10-3 Pa.s) and similar to those of IPM. Under these conditions, the low water fraction favors W/O emulsion whereas the low temperature favors O/W emulsion. When the composition variable (fw) and the formulation variable (temperature) are conflicting the system adopts a o/W/O morphology.54 A catastrophic inversion takes place at fw = 0.15 with a large increase of viscosity (4·10-1 Pa.s). Then, the addition of water decreases both the interaction of oil droplets and the viscosity (5·10-3 Pa.s at fw = 0.8). From fw = 0.15 to 0.8, the internal oil phase content is the most important variable as far as the viscosity of the emulsion is concerned. The variation is essentially exponential, as indicated by an almost straight line with a log scale, as several empirical formulas have suggested.55 The viscosity should decrease as fw tends to unity, but due to the poor solubility of Brij30 in water (or to the too low IPM quantity for total solubilization of Brij30), the dispersion of insoluble surfactants results in a final increase in viscosity (3.5 10-2 Pa.s).

18


Page 19 of 37

1.E+01

0.100

fw=1.0

Viscosity (Pa.s)

IPM

1.E+00

fw=0.0 0.010

NaCl 10-2M

0.001

Viscosity (Pa.s))

1.E-01

0.000 10

o/W/O

1.E-02

1.E-03

20

30


60

70

80

Dispersion of Brij30

O/W (20°C)

W/O (80°C)

w/O/W

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1.E-04 0

0.2

0.4

0.6

0.8

1

fw Figure 8. Viscosity versus fw at 20 °C (▲) and 80 °C () for 9% Brij30/IPM/10-2M NaCl(aq) at 500 s-1 obtained from curves in figure 7, with localization of o/W/O, w/O/W, o/W/O, O/W and Brij30 dispersion areas. Inset: Viscosity at 500 s-1 from 10 to 80°C, of IPM (), IPM with 9% Brij30 (fw=0.0, ), NaCl(aq) 10-2M (—‒) and NaCl(aq) 10-2M with 9% Brij30 (fw=1.0, ‒ ‒ ).

At 80°C, for fw < 0.5 the almost constant viscosity (2·10-3 Pa.s) of the W/O emulsion corresponds to the one of the external oily phase. When fw increases water droplets become more numerous and start interacting which each other. At high internal phase content, close to the catastrophic branch of the inversion line, the viscosity increases until fw = 0.95 (η = 26 10-3 Pa.s). An abrupt change on apparent viscosity after fw = 0.9 indicates that the catastrophic inversion border is passed.

4. Conclusion A viscosity minimum associated to the vicinity of “optimal formulation” can been used to track such physicochemical conditions as it was suggested a long time ago.36 Allouche et al.

24

and Tyrode et

al56 detected the phase inversion of emulsion with temperature using a Rheomixer Emulsification Cell. This home-made Rheomixer is not commercially available and requires at least 100 mL of emulsion. We have used here a classical commercial Rheometer, taking advantage of the simultaneous fluid mixing and rheological measurement that can be achieved with only 2 mL of sample, or less if the viscosity difference between the aqueous and oil phase is more important. The shear rate (500 s-1) applied by cone-plate geometry is homogeneous and provides an agitation 19



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Page 20 of 37

sufficient to allow a reversible phase inversion during a heating-cooling cycle. All PIT values obtained by rheology match the ones obtained by specific conductivity, within the accuracy of the devices (1-2°C).

This method naturally provides the viscosity of emulsions throughout the formulation (T)composition (fw) maps. The transitional inversion line and the catastrophic branches have been determined for the 9% Brij30/IPM/10-2M NaCl(aq) system. The transitional inversion is obtained from the PIT data and the catastrophic inversion by the abrupt viscosity change.

5. Acknowledgments Chevreul Institute (FR 2638), Ministère de l’Enseignement Supérieur et de la Recherche, Région Nord – Pas de Calais and FEDER are acknowledged for supporting and funding partially this work.

6. References (1) (2) (3) (4) (5)

(6) (7) (8) (9) (10) (11)

(12) (13)

(14) (15)

(16)

Bancroft, W. D. The Theory of Emulsification. J. Phys. Chem. 1913, 17, 501. Bancroft, W. D. Theory of Emulsification. VI. J. Phys. Chem. 1915, 19, 275. Griffin, W.C. Classification of Surface-Active Agents by HLB. Journal of the Society of Cosmetic Chemists 1 (1949): 311. 1949. Shinoda, K.; Arai, H. The Correlation between Phase Inversion Temperature in Emulsion and Cloud Point in Solution of Nonionic Emulsifier. J. Phys. Chem. 1964, 68, 3485. Shinoda, K.; Saito, H. Stability of O/W [oil/water] Type Emulsions as Functions of Temperature and the HLB [hydrophile-Lipophile Balance] of Emulsifiers: The Emulsification by PIT [phase Inversion Temperature]-Method. J. Colloid Interface Sci. 1969, 30, 258. Esquena, J.; Sankar, G. R.; Solans, C. Highly Concentrated W/O Emulsions Prepared by the PIT Method as Templates for Solid Foams. Langmuir 2003, 19, 2983. Reed, R. L.; Healy, R. N. Some Physicochemical Aspects of Microemulsion Flooding: A Review. In Improved Oil Recovery Surfactant Polym. Flooding, [Pap. AIChE Symp.] ; Academic, 1977; pp 383–437. Bourrel, M.; Graciaa, A.; Schechter, R. S.; Wade, W. H. The Relation of Emulsion Stability to Phase Behavior and Interfacial Tension of Surfactant Systems. J. Colloid Interface Sci. 1979, 72, 161. Bourrel, M.; Salager, J. L.; Schechter, R. S.; Wade, W. H. A Correlation for Phase Behavior of Nonionic Surfactants. J. Colloid Interface Sci. 1980, 75, 451. Salager, J.-L.; Anton, R. E.; Anderez, J. M.; Aubry, J.-M. Formulation Des Microémulsions Par La Méthode Du HLD. Tech. L’Ingénieur Vol Génie Procédés (2001) 157. 2001. Salager, J. L.; Loaiza-Maldonado, I.; Miñana-Perez, M.; Silva, F. Surfactant-Oil-Water Systems near the Affinity Inversion. Part I: Relationship between Equilibrium Phase Behavior and Emulsion Type and Stability. J. Dispers. Sci. Technol. 1982, 3, 279. Salager, J.-L.; Moreno, N.; Anton, R.; Marfisi, S. Apparent Equilibration Time Required for a SurfactantOil-Water System to Emulsify into the Morphology Imposed by the Formulation. Langmuir 2002, 18, 607. Alvarez, G.; Anton, R.; Marfisi, S.; Marquez, L.; Salager, J.-L. Apparent Equilibration Time Required for Surfactant-Oil-Water Systems to Emulsify into the Morphology Imposed by the Formulation. Part 2: Effect of Sec-Butanol Concentration and Initial Location. Langmuir 2004, 20, 5179. Lira, K. H.; Smith, D. H. Electrical Conductivities of Concentrated Emulsions and Their Fit by Conductivity Models. J. Dispers. Sci. Technol. 1990, 11, 529. Lee, J.-M.; Shin, H.-J.; Lim, K.-H. Morphologies of Three-Phase Emulsions of the Ternary Nonionic Amphiphile/oil/water Systems and Their Determination by Electrical Method. J. Colloid Interface Sci. 2003, 257, 344. Araujo, E. S.; de Oliveira, H. P. Phase Inversions in Emulsions Probed by Electrical Impedance 20


Page 21 of 37

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(17) (18) (19) (20) (21) (22) (23)

(24)

(25) (26) (27) (28) (29)

(30) (31) (32)

(33)

(34)

(35) (36)

(37)

(38) (39) (40)

Spectroscopy. J. Dispers. Sci. Technol. 2011, 32, 1649. Lehnert, S.; Tarabishi, H.; Leuenberger, H. Investigation of Thermal Phase Inversion in Emulsions. Colloids Surf. Physicochem. Eng. Asp. 1994, 91, 227. Sjoblom, J.; Fordedal, H.; Skodvin, T.; Gestblom, B. Emulsions Characterized by Means of Time Domain Dielectric Measurements (TDS). Technical Applications. J. Dispers. Sci. Technol. 1999, 20, 921. Asami, K. Characterization of Heterogeneous Systems by Dielectric Spectroscopy. Prog. Polym. Sci. 2002, 27, 1617. Pizzino, A.; Rodriguez, M. P.; Xuereb, C.; Catté, M.; Van Hecke, E.; Aubry, J.-M.; Salager, J.-L. Light Backscattering as an Indirect Method for Detecting Emulsion Inversion. Langmuir 2007, 23, 5286. Pizzino, A.; Catté, M.; Van Hecke, E.; Salager, J.-L.; Aubry, J.-M. On-Line Light Backscattering Tracking of the Transitional Phase Inversion of Emulsions. Colloids Surf. Physicochem. Eng. Asp. 2009, 338, 148. Charin, R. M.; Nele, M.; Tavares, F. W. Transitional Phase Inversion of Emulsions Monitored by in Situ Near-Infrared Spectroscopy. Langmuir 2013, 29, 5995. Aske, N.; Kallevik, H.; Sjoblom, J. Water-in-Crude Oil Emulsion Stability Studied by Critical Electric Field Measurements. Correlation to Physico-Chemical Parameters and near-Infrared Spectroscopy. J. Pet. Sci. Eng. 2002, 36, 1. Allouche, J.; Tyrode, E.; Sadtler, V.; Choplin, L.; Salager, J.-L. Simultaneous Conductivity and Viscosity Measurements as a Technique To Track Emulsion Inversion by the Phase-Inversion-Temperature Method. Langmuir 2004, 20, 2134. Anisa, A. N. I.; Nour, A. H.; Nour, A. H. Catastrophic and Transitional Phase Inversion of Water-in-Oil Emulsion for Heavy and Light Crude Oil. J. Appl. Sci. 2010, 10, 3076. Winsor, P. A. Solvent Properties of Amphiphilic Compounds.; Butterworths Sci. Pubs., 1954. Kahlweit, M.; Strey, R.; Firman, P. Search for Tricritical Points in Ternary Systems: Water-Oil-Nonionic Amphiphile. J. Phys. Chem. 1986, 90 (4), 671. Queste, S.; Salager, J. L.; Strey, R.; Aubry, J. M. The EACN Scale for Oil Classification Revisited Thanks to Fish Diagrams. J. Colloid Interface Sci. 2007, 312 (1), 98. Ontiveros, J. F.; Pierlot, C.; Catté, M.; Molinier, V.; Pizzino, A.; Salager, J.-L.; Aubry, J.-M. Classification of Ester Oils according to Their Equivalent Alkane Carbon Number (EACN) and Asymmetry of Fish Diagrams of C10E4/ester Oil/water Systems. J. Colloid Interface Sci. 2013, 403, 67. Wade, W. H.; Morgan, J. C.; Schechter, R. S.; Jacobson, J. K.; Salager, J. L. Interfacial Tension and Phase Behavior of Surfactant Systems. Soc. Pet. Eng. J. 1978, 18, 242. Salager, J. L.; Bourrel, M.; Schechter, R. S.; Wade, W. H. Mixing Rules for Optimum Phase-Behavior Formulations of Surfactant/oil/water Systems. Soc. Pet. Eng. J. 1979, 19, 271. Graciaa, A.; Lachaise, J.; Sayous, J. G.; Grenier, P.; Yiv, S.; Schechter, R. S.; Wade, W. H. The Partitioning of Complex Surfactant Mixtures between Oil/water/microemulsion Phases at High Surfactant Concentrations. J. Colloid Interface Sci. 1983, 93, 474. Graciaa, A.; Anderez, J.; Bracho, C.; Lachaise, J.; Salager, J.-L.; Tolosa, L.; Ysambertt, F. The Selective Partitioning of the Oligomers of Polyethoxylated Surfactant Mixtures between Interface and Oil and Water Bulk Phases. Adv. Colloid Interface Sci. 2006, 123-126, 63. Ilic, M. A.; Haegel, F.-H.; Pavelkic, V. M.; Zlatanovic, S. J.; Markovic, Z. S.; Cvjetic, A. S. Unusually Sluggish Microemulsion System with Water, Toluene and a Technical Branched Alkyl Polyethoxylate. Chem. Ind. Chem. Eng. Q. 2015, 21, 429. Marquez, L.; Graciaa, A.; Lachaise, J.; Salager, J.-L.; Zambrano, N. Hysteresis Behavior in TemperatureInduced Emulsion Inversion. Polym. Int. 2003, 52, 590. Salager, J. L.; Miñana-Perez, M.; Anderez, J. M.; Grosso, J. L.; Rojas, C. I.; Layrisse, I. Surfactant-OilWater Systems near the Affinity Inversion. Part II: Viscosity of Emulsified Systems. J. Dispers. Sci. Technol. 1983, 4, 161. Pizzino, A.; Molinier, V.; Catté, M.; Ontiveros, J. F.; Salager, J.-L.; Aubry, J.-M. Relationship between Phase Behavior and Emulsion Inversion for a Well-Defined Surfactant (C10E4)/n-Octane/Water Ternary System at Different Temperatures and Water/Oil Ratios. Ind. Eng. Chem. Res. 2013, 52, 4527. Kunieda, H.; Fukui, Y.; Uchiyama, H.; Solans, C. Spontaneous Formation of Highly Concentrated Water-inOil Emulsions (gel-Emulsions). Langmuir 1996, 12 (9), 2136. Burauer, S.; Sachert, T.; Sottmann, T.; Strey, R. On Microemulsion Phase Behavior and the Monomeric Solubility of Surfactant. Phys. Chem. Chem. Phys. 1999, 1 (18), 4299. Pizzino, A.; Molinier, V.; Catté, M.; Salager, J.-L.; Aubry, J.-M. Bidimensional Analysis of the Phase Behavior of a Well-Defined Surfactant (C 10 E 4 )/Oil ( n -Octane)/Water−Temperature System. J. Phys. Chem. B 2009, 113 (50), 16142. 21



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(41)

(42) (43) (44) (45) (46) (47)

(48) (49)

(50)

(51)

(52)

(53)

(54)

(55) (56)

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Tolosa, L.-I.; Forgiarini, A.; Moreno, P.; Salager, J.-L. Combined Effects of Formulation and Stirring on Emulsion Drop Size in the Vicinity of Three-Phase Behavior of Surfactant-Oil Water Systems. Ind. Eng. Chem. Res. 2006, 45, 3810. Boyd, J.; Parkinson, C.; Sherman, P. Factors Affecting Emulsion Stability, and the HLB [hydrophilicLipophilic Balance] Concept. J. Colloid Interface Sci. 1972, 41, 359. Milos, F. S.; Wasan, D. T. Emulsion Stability of Surfactant Systems near the Three-Phase Region. Colloids Surf. 1982, 4, 91. Anton, R. E.; Salager, J. L. Emulsion Instability in the Three-Phase Behavior Region of Surfactant-AlcoholOil-Brine Systems. J. Colloid Interface Sci. 1986, 111, 54. Hazlett, R. D.; Schechter, R. S. Stability of Macroemulsions. Colloids Surf. 1988, 29, 53. Kabalnov, A.; Weers, J. Macroemulsion Stability within the Winsor III Region: Theory versus Experiment. Langmuir 1996, 12, 1931. Miñana-Perez, M.; Jarry, P.; Perez-Sanchez, M.; Ramirez-Gouveia, M.; Salager, J. L. Surfactant-Oil-Water Systems near the Affinity Inversion. Part V: Properties of Emulsions. J. Dispers. Sci. Technol. 1986, 7, 331. Salager, J. L. Emulsion Properties and Related Know-How to Attain Them. In Pharmaceutical emulsions and suspensions; Nielloud, F., Marti-Mestres, G., Eds.; CRC Press, 2000; Vol. 105, pp 73–125. Tyrode, E.; Mira, I.; Zambrano, N.; Márquez, L.; Rondón-Gonzalez, M.; Salager, J.-L. Emulsion Catastrophic Inversion from Abnormal to Normal Morphology. 3. Conditions for Triggering the Dynamic Inversion and Application to Industrial Processes. Ind. Eng. Chem. Res. 2003, 42 (19), 4311. Rondón-Gonzaléz, M.; Sadtler, V.; Choplin, L.; Salager, J.-L. Emulsion Catastrophic Inversion from Abnormal to Normal Morphology. 5. Effect of the Water-to-Oil Ratio and Surfactant Concentration on the Inversion Produced by Continuous Stirring. Ind. Eng. Chem. Res. 2006, 45 (9), 3074. Zambrano, N.; Tyrode, E.; Mira, I.; Márquez, L.; Rodríguez, M.-P.; Salager, J.-L. Emulsion Catastrophic Inversion from Abnormal to Normal Morphology. 1. Effect of the Water-to-Oil Ratio Rate of Change on the Dynamic Inversion Frontier. Ind. Eng. Chem. Res. 2003, 42 (1), 50. Mira, I.; Zambrano, N.; Tyrode, E.; Márquez, L.; Peña, A. A.; Pizzino, A.; Salager, J.-L. Emulsion Catastrophic Inversion from Abnormal to Normal Morphology. 2. Effect of the Stirring Intensity on the Dynamic Inversion Frontier. Ind. Eng. Chem. Res. 2003, 42 (1), 57. Miñana-Perez, M.; Jarry, P.; Perez-Sanchez, M.; Ramirez-Gouveia, M.; Salager, J. L. Surfactant-Oil-Water Systems near the Affinity Inversion. Part V: Properties of Emulsions. J. Dispers. Sci. Technol. 1986, 7, 331. Salager, J. L.; Miñana-Perez, M.; Perez-Sanchez, M.; Ramirez-Gouveia, M.; Rojas, C. I. Surfactant-OilWater Systems near the Affinity Inversion. Part III: The Two Kinds of Emulsion Inversion. J. Dispers. Sci. Technol. 1983, 4, 313. Pal, R. Viscosity-Concentration Equation for Emulsions of Nearly Spherical Droplets. J. Colloid Interface Sci. 2000, 231, 168. Tyrode, E.; Allouche, J.; Choplin, L.; Salager, J.-L. Emulsion Catastrophic Inversion from Abnormal to Normal Morphology. 4. Following the Emulsion Viscosity during Three Inversion Protocols and Extending the Critical Dispersed-Phase Concept. Ind. Eng. Chem. Res. 2005, 44, 67.

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Page 23 of 37

0.10

900 5

0.01

450 300 150

0.00 49

54

59

Temperature (°C)

Cone Rheometer

Phase Inversion Temperature


2

20

50

10

5

5 100

50

10

30 20

0 44

10

70

Temperature (°C)

600

Conductivity (mS.cm-1)

2

750

Viscosity (Pa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42


10

10

0

100

0.25

50

20

0.5

fw

10

5

0.75

Formulation-Composition Map

1


80 Tu

Winsor I Winsor III

70

Winsor II Winsor IV

Temperature (°C)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 37

60

PITRheo

50 T* 40

30 C*

C0 20 0

5

10

15

Surfactant (%)


20

25

Page 25 of 37


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60



0.10

900 800



600



0.01

500 400 300

200 100 0.00

0 44

46

48

50


56


58

60

62


700

Viscosity (Pa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 26 of 37

1 2 900 3 4 800 5 6 700 7 8 600 9 10 500 11 12 13400 14 15300 16 17200 18 19100 20 210 22 62 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60



Page 27 of 37



1 200

A

Conductuvity (mS.cm-1)

1 000 6% Brij30 800

9% 600

12% 15%

400

18% 21%

200

0 10

20

30


60

70

80

1

B 21% Brij30

18% 0.1

Viscosity (Pa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 28 of 37

15% 12% 6%

0.01

9%

0.001 10

20

30



60

70

80

Page 29 of 37


1 2 3 A 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 80 23 24 25 26 27 28 B 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 80 48 49 50 51 52 53 54 55 56 57 58 59 60



1000

A

0.7 900

0.6

0.5

800

0.4

Conductivity (µS.cm-1)

700 600

0.3

500 400

0.8

300 200

fw = 0.9

100 0 10

0.1

20

30


60

70

80

fw=0.3

B

0.4

0.5 0.6

0.01

0.3

0.4

0.5

0.8

0.6

0.7

0.7

0.8

Viscosity (Pa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 30 of 37

0.001 10

20

30



60

70

80

Page 31 of 37


0.3

1 2 3 A 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 80 23 24 25 26 27 28 29 B 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 80 48 49 50 51 52 53 54 55 56 57 58 59 60



“A” Profile

fw = 0.6

fw > 0.6

“B” Profile

Max1

fw < 0.6

Max2



w/o



Min 1



o/w 

PIT

Viscosity

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 32 of 37

o/w

w/o

w/o

o/w

Temperature


Page 33 of 37


1 2 3 4 ofile 5 6 7 w/o 8 9 10 11 12 13 14 15 ture 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60



1000

Viscosity (mPa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 34 of 37

100 Min1 Max1 PIT Max2

10

1

0.3

0.4

0.5

0.6 fw

0.7

0.8


0.9

Page 35 of 37

80

A

2 2

70 6 4

60

8

10

10

Temperature (°C)

6 2

50

7

17

5

40

30

8

Fish

20

10

25

10

15

50

40

20

30 100

200

10

30

20

300 300

10 0

2

4

6

8

10

12 % TA

14

16

18

20

22

24

80 2

B

2 2

5

10

2

20

70 3

50

2.8

60

Temperature (°C)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


10

5

5 8

15

15

4

12

18

5

15

15

100

50 28

68 120

7

40 7.5

15

10 5

30

5 15

20

4

20 10

10 0

0.1

100 0.2

50 0.3

0.4

20 0.5

10 0.6

fw


0.7

5 0.8

0.9

1


1 2 23 4 5 6 67 88 9 10 10 11 12 13 14 15 16 50 17 18 19 100 20 21 300 22 23 300 24 25 22 24 26 27 28 29 30 2 31 32 33 5034 35 5 36 37 100 38 39 40 0 41 42 43 10 44 45 46 20 47 48 49 50 51 0.9 1 52 53 54 55 56 57 58 59 60


Page 36 of 37

Page 37 of 37

1.E+01

0.100

fw=1.0

Viscosity (Pa.s)

IPM

1.E+00

fw=0.0 0.010

NaCl 10-2M

0.001

1.E-01

0.000 10

o/W/O

1.E-02

1.E-03

20

30


60

70

80

Dispersion of Brij30

O/W (20°C)

W/O (80°C) w/O/W

Viscosity (Pa.s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1.E-04 0

0.2

0.4

0.6 fw


0.8

1

Cone–Plate Rheometer as Reactor and Viscosity Probe for the

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