Interfacial aging

Chen, J., Dickinson, E. (1999a). Interfacial ageing effect on the rheology of heat-set protein emulsion gel. Food Hydrocolloids, 13, 363-369. 

Figures 3 and 4 compare the interfacial aging behavior of lemon oil 2 and 1 respectively. As in the case of orange oil, aging behavior is a function of temperature and lemon oil used. At 45 and 50 C, the lemon oil 1/water interface aged to an IFT value too low to measure in 3 to 4 hrs. The lemon oil 2/water interface retained a finite value after 10 hrs. at 50 C. The rate of aging for both lemon oils decreases significantly as the temperature decreases,...

Figures 6-11 contain IFT aging curves for several supernatant phases against citrus oils. Figure 6 shows the interfacial aging of a G/A supernatant phase against orange oil 2. At 45 and 50 C,...

Figures 6 and 12 contain IFT aging curves at 35 and 50°C that show the IFT of the G/A complex coacervate phase/orange oil 2 interface is clearly lower than that of the supernatant/orange oil 2 interface at all interfacial ages examined. At 45°C, IFT values of the interface formed with the complex coacervate phase are slightly lower than that of the supernatant phase at 45°C. At 40°C, both phases have about the same IFT aging curve. These data indicate that wetting (and encapsulation) of orange oil 2 by a G/A complex coacervate phase will occur readily at 35 or 50°C, but there could be a problem at intermediate temperature.

Modem drop volume tensiometers are connected to a computer with sophisticated software that can be used to automatically record the surface tension as a function of the true interfacial age. Adsorption kinetics experiments with the drop volume technique can be conducted using either the constant drop formation method or the quasistatic method (for details, see Commentary). The choice of the dynamic measurement method depends primarily on the time range over which the adsorption kinetics needs to be measured. 

The drop volume and drop shape techniques provide multiple interfacial tension values as a function of the interfacial age for a given surfactant at a given concentration at a specific temperature. Examples are provided in unitd3.5 (see Fig. D3.5.6). 

Two timescales can be distinguished in the adsorption process of ionic species. The first timescale is characterized by the diffusion relaxation time of the EDL, = 1 / (D,k /) see Equations 5.32 and 5.34 above. It accounts for the interplay of electrostatic interactions and diffusion. The second scale is provided by the characteristic time of the used experimental method, tgxp, that is, the minimum interfacial age that can be achieved with the given method typically,... 

Crystalline structures were found to develop upon interfacial aging of the Cut 3-caustic system (Figure 2). (This photograph was... 

In studies on Pt dotted silicon electrodes, PMC measurements revealed that tiny Pt dots increased the interfacial charge transfer compared with bare silicon surfaces in contact with aqueous electrolytes. However, during an aging effect, the thickness of the oxide layer between the silicon and the platinum dots gradually increased so that the kinetic advantage again decreased with time.11... 

Caustic Waterflooding. In caustic waterflooding, the interfacial rheologic properties of a model crude oil-water system were studied in the presence of sodium hydroxide. The interfacial viscosity, the non-Newtonian flow behavior, and the activation energy of viscous flow were determined as a function of shear rate, alkali concentration, and aging time. The interfacial viscosity drastically... 

The interfacial chemistry of corrosion-induced failure on galvanized steel has been investigated (2) adhesion of a polyurethane coating was not found to involve chemical transformations detectable by XPS, but exposure to Kesternich aging caused zinc diffusion into the coating. Similar results were obtained with an alkyd coating. Adhesion loss was proposed to be due to formation of a weak boundary layer of zinc soaps or water-soluble zinc corrosion products at the paint metal Interface. 

Failure occurred primarily in the adhesive for up to 5 days exposure in these aging environments. After 5 days, a mixture of failure sites could be identified with more than one interface often exposed on a given sample. This indicated that during extended exposure to humid environments, any non-uniformity or interfacial weakness could be attacked and eventually become the locus of failure. 

Fig. 23 a Image of a microfluidic chip used for IFT measurements filled with liquid dye to illuminate channels. To perform the measurement, drops are injected (fluid la and b) are injected into an immiscible stream (2). Additional immiscible matrix is added (3a and 3b) conveying the drops into channel 4 for analysis and measurement. Constrictions in channel 4 accelerate/stretch the drops. Multiple constrictions enable measurement at different interface age. The channel geometry is shown schematically in the inset (from [108]). b Interfacial tension (ct) of water/ethylene glycol mixtures (binary drops) in PDMS oil, as a function of composition ((j)). (Reproduced with permission from [109])... 

In contrast to this, physical chemists in U.S. universities seem—perhaps partly because of the absence of a modem textbook in English—out of touch with the revolution in fundamental interfacial electrochemistry which has occurred since 1950. The fragments of electrochemistry which are taught in many U.S. universities belong not to the space age of electrochemically powered vehicles, but to the age of... 

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