Emulsion schematic illustration

The surfactant is initially distributed through three different locations dissolved as individual molecules or ions in the aqueous phase, at the surface of the monomer drops, and as micelles. The latter category holds most of the surfactant. Likewise, the monomer is located in three places. Some monomer is present as individual molecules dissolved in the water. Some monomer diffuses into the oily interior of the micelle, where its concentration is much greater than in the aqueous phase. This process is called solubilization. The third site of monomer is in the dispersed droplets themselves. Most of the monomer is located in the latter, since these drops are much larger, although far less abundant, than the micelles. Figure 6.10 is a schematic illustration of this state of affairs during emulsion polymerization. 

Fig. 8 Schematic illustration of different types of instability of emulsions.

The performance equation for the model is obtained from the continuity (material-balanoe) equations for A over the three main regions (bubble, cloud + wake, and emulsion), as illustrated schematically in Figure 23.7. Since the bed is isothermal, we need use only the continuity equation, which is then uncoupled from the energy equation. The latter is required only to establish the heat transfer aspects (internally and externally) to achieve the desired value of T. 

Fig. 9.16 Schematic illustration of drying process for SWNT-filled polymer emulsion. Initially the nanotubes and polymer particles are uniformly suspended in water (left). Once most of water has evaporated, the polymer particles assume a close-packed configuration with the nanotubes occupying interstitial space(center). Finally, the polymer particles will interdiffuse (i.e., coalesce) to forma coherent film, locking the SWNTs within a segregated network (right) (Keren et al, 2003. With permission from Wiley-VCH)...

Emulsion polymerization is applicable only to monomers that are relatively insoluble in water, such as styrene. A coarse emulsion of monomer in aqueous surfactant is prepared with a water-soluble initiator, say, H202 in the solution. The surfactant concentration is above the CMC, so surfactant molecules are present as monomers, micelles, and emulsifiers at the oil-water interface. Even an insoluble liquid like styrene dissolves in water to some extent. Therefore the monomer is present in coarse emulsion drops, solubilized in micelles, and as dissolved molecules in water. A schematic illustration of the distribution of surfactant, monomer, and polymer in an emulsion polymerization process is shown in Figure 8.14. 

We studied electrochemically induced ET between a ferrocene derivative (FeCp-X) in single oil droplets and hexacyanoferrate(III) (Fe(III)) in the surrounding water phase the reaction system is schematically illustrated in Figure 11 [50,74], Tri-n-butyl phosphate (TBP) containing FeCp-X (ferrocene [X = H] or decamethylferrocene [X = DCM]), a fluorescent dye (perylene [Pe 0.5 mM] or 9,10-diphenylanthracene [DPA 10 mM]), and TBA+TPB (lOmM) is dispersed in an aqueous solution containing TBA+Cr, MgS04 (0.1 M), and potassium hexacyanoferrate(II) (Fe(II) 0.2 mM) with a 1 500 (oil/water) weight ratio as a sample emulsion. 

A form of liquid membrane that received a great deal of attention in the 1970s and 1980s was the bubble or emulsion membrane, first developed by Li at Exxon [11-13], Figure 11.14 is a schematic illustration of an emulsion liquid membrane process, which comprises four main operations. First, fresh product solution is emulsified in the liquid organic membrane phase. This water/oil emulsion then enters a large mixer vessel, where it is again emulsified to form a water/oil/water emulsion. Metal ions in the feed solution permeate by coupled... 

Latex IPNs. Latex IPNs are the third type of IPNs and are manufactured according to the general schematic illustrated in Figure 3. Latex IPN synthesis involves the initial synthesis of a crosslinked seed polymer, usually in the form of an aqueous latex. The seed latex is then swollen with a second monomer/crosslinker/initiator system which is then polymerized "in situ" to form an aqueous IPN emulsion. Materials of this type are best suited to coating applications as illustrated by the development of "Silent Paint" by Sperling et al ( ). However, latex IPNs are limited to water emulsifiable monomer/polymer systems, most of which have fairly low service temperatures, less than 150 C. 

Zn(II) was employed as a print molecule because of its strong interaction with the bifunctional monomer, DDDPA. Divinylbenzene, L-glutamic acid dioleylester ribitol and toluene were used as matrix-forming monomer, emulsion stabiliser and diluent, respectively. After polymerisation, the print molecules were removed from the resin, upon which selective recognition sites were formed. The schematic illustration of surface template polymerisation with DDDPA is shown in Scheme 9.8. The Zn(II)-imprinted resins were ground into particles, whose volume-averaged diameters were ca. 40 pm. The yield was ca. 80%. 

Single Emulsions. These emulsions are formed by two immiscible phases (e.g. oil and water), which are separated by a surfactant film. The addition of a surfactant (or emulsifier) is necessary to stabilize the drops. The emulsion containing oil as dispersed phase in the form of fine droplets in aqueous phase is termed as oil-inwater (0/W) emulsion, whereas the emulsion formed by the dispersion of water droplets in the oil phase is termed as water-in-oil (W/0) emulsion. Figure 1 schematically illustrates the 0/W and W/0 type emulsions. Milk is an example of naturally occurring 0/W emulsion in which fat is dispersed in the form of fine droplets in water. 

Fig. 8-9 Schematic illustration of the preparation of catalytic silica by surface imprinting in the presence of TSA as a template by use of the water-in-oil emulsion technique...

Figure 24. Schematic illustration of destabilization of HMPAA emulsion by addition of salt.

The first step in all interfacial polymerization processes for encapsulation is to form an emulsion. This is followed by initiation of a polymerization process to form the capsule wall. Most commercial products based on interfacial or in situ polymerization employ water-immiscible liquids. For encapsulation of a water-immiscible oil, an oil-in-water emulsion is first formed. Four processes are schematically illustrated in Figure 5.82. In Figure 5.82(a), reactants in two immiscible phases react at the interface forming the polymer capsule wall. For example, to encapsulate a water-immiscible solvent, multifunctional acid chlorides or isocyanates are dissolved in the solvent and the solution is dispersed in water with the aid of a polymeric emulsifier, e.g., poly(vinyl alcohol). When a polyfunctional water-soluble amine is then added with stirring to the aqueous phase, it diffuses to the solvent-water interfece where it reacts with acid chlorides or isocyanates forming the insoluble polymer capsule wall. Normally some reactants with more than two functional groups are used to minimize a regation due to the formation of sticky walls. 

Figure 210 2 Schematic representation of the early stages of emulsion polymerization illustrating three scales of observation macroscopic, microscopic and submicroscopic. (Reprinted with permission from E. D. Sudol, E. S. Daniels and M. S. El-Aasser, in Polymer Latexes Preparation, Characterization, and Applications, E. S. Daniels, E. D. Sudol and M. S. El-Aasser, (eds), ACS Symp. Sen, Vol. 492, 1992, p 1 Copyright 1992 American Chemical Society)...

Figure 19 Schematic illustration of the capillary condensate formed between glass surfaces due to breakdown of adsorbed emulsion droplets. The figure is not according to scale. (From Ref. 81, with permission.)...

Figure 2 Schematic illustration of a two-step process in formation of a double emulsion.

Figure 14 Schematic illustration of possible organization and stabilization mechanism of BSA and monomeric emulsifiers (Span 80) at the two interfaces of double emulsion.

Figure 18 Schematic illustration of the putative process of emulsion breakdown during the measurement of cef in W/O emulsions (see Refs 20 and 85-92 for detailed discussion of the method and phenomenon Ref. 93 describes our application).

Figure 5.4 (a) Schematic illustration of a capillary microfluidic device for making O/W/O emulsions, (b, c) Optical microscope images of (b) emulsions and (c) PDMAEMA microcapsules in pH 7.4 buffer solution. The scale bar is 100 pm. The compositions of the middle fluid are 1.0 mol DMAEMA,... 

Figure 21.1 Schematic illustration of typical double emulsions, (a) W1/O/W2 emulsion (b) O1/W/O2 emulsion.

Figure 21.2 Schematic illustration of the two-step homogenization for producing W/O/W emulsions, (a) Step 1 high-shear mixing to produce a fine W/O emulsion, (b) Step 2 low-shear mixing to produce a W/O/W emulsion.

Figure 21.6 Controlled production of monodisperse double emulsions in a two consecutive microfluidic junctions [82, 83]. (a) Schematic illustration of two consecutive T-junctions for producing W/O/W droplets (b) formation of W/O/W emulsion with single core in a glass microchannel. The channel has a uniform depth of 100pm. Scale bar is 200pm.

FIGURE 3 Schematic illustrations of the main layers in a typical chromogenic color emulsion. The color sensitivity of the active layers is shown on the left-hand side, and the colors formed after development are given on the right-hand side. 

F re4.6 Schematic illustration of pigment encapsulation through an emulsion-like polymerization reaction. The process involves ... 

The multiple emulsion is prepared by a two-stage process, as schematically illustrated in Figure 22. The primary emulsion is prepared by adding the aqueous phase to an oil solution of the polymeric emulsifier 1 with a low HLB number, e.g., Aralcel PI 35, using... 

Methods of nanoemulsion preparation have been described in detail. A schematic illustration of the overall process is depicted in Figure 12.2. Three different approaches can be used to incorporate the drug and/or the various components in the aqueous or oil phase. The most common approach is to dissolve the water-soluble ingredients in the aqueous phase and the oil-soluble ingredients in the oil phase. The second approach, which is used in fat emulsion preparations involves the dissolution of an aqueous-insoluble emulsifier in alcohol and then the dispersion of the alcohol solution in water followed by evaporation and total removal of the alcohol until a fine dispersion of the emulsifier in the aqueous phase is reached. The third approach, which is mainly used for hydrophobic drug... 

Figure 4.51 Schematic illustration of an emulsion-made core-shell impact modifier particle...

FIGURE 9.1 Schematic illustration of model of emulsion polymerization by Harkins. 

Figure 13.1 Schematic illustration of basic emulsion types. The white color represents the aqueous phase, for example water and the gray color represents the oily phase, for example oil.

A clear demonstration of the phase inversion that occurs on heating an emulsion is illustrated from a study of the phase behavior of emulsions as a function of temperature. This is illustrated in Fig. 2.10 which shows schematically what happens when the temperature is increased [13,14]. At low temperature, over the Winsor 1 region, 0/W macroemulsions can be formed and are quite stable. On increasing the temperature, the 0/W emulsion stability decreases and the macroemulsion finally resolves when the system reaches the Winsor 111 phase region (both 0/W and W/0 emulsions are unstable). At higher temperature, over the Winsor 11 region, W/0 emulsions become stable. 

---