Image development, particle/ionic

Figure 8.14 CLSM images showing the initial development of the microstructure of a phase-separated mixed biopolymer system (25.5 wt% sugar, 31.4 wt% glucose syrup, 7 wt% gelatin, and 4 wt% oxidized starch pH = 5.2, low ionic strength) containing 0.7 wt% polystyrene latex particles (d32 = 0.3 pm). The sample was quenched from 90 to 1 °C, held at 1 °C for 10 min, heated to 40 °C at 6 °C min-1, and observed at 40 °C for various times (a) 2 min, (b) 4 min, (c) 8 min, and (d) 16 min. White regions are rich in colloidal particles. Reproduced from Firoozmand et ai (2009) with permission.

The description of a colloid should include particle size, mobility, charge and their distributions, charge/mass ratio, electrical conductivity of the media, concentration and mobility of ionic species, the extent of a double layer, particle-particle and particle-substrate interaction forces and complete interfacial analysis. The application of classical characterization methods to nonaqueous colloids is limited and, for this reason, the techniques best suited to these systems will be reviewed. Characteristic results obtained with nonaqueous dispersions will be summarized. Physical aspects, such as space charge effects and electrohydrodynamics, will receive special attention while the relationships between chemical and physical properties will not be addressed. An application of nonaqueous colloids, the electrophoretic development of latent images, will also be discussed. 

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