Tiny microcapsules

An electron microscope image of a drug capsule as it bursts open, revealing the tiny microcapsules inside. The image has been digitally colored. 

Pressure-indicating film can be used to verify the amount of load applied on the package. The film contains tiny microcapsules of colored dye. These microcapsules rupture depending on the amount of pressure applied on the film, producing a pressure footprint. The results are not extremely precise, but can be used to estimate the amount of load applied, as a first pass approximation. 

Colour formation reactions of this type are utilised in carbonless copy paper, which is based on the principle of colour formation on the copy as a result of pressure of writing or typing in the master sheet. In such systems, the underside of the master sheet contains the colour former, for example compound 243, encased in microcapsules, which are tiny spheres with a hard polymer outer shell. Pressure on the master sheet breaks the microcapsules and allows the colour former to come into contact with an acidic reagent coated on the copy sheet, thus causing an irreversible colour formation reaction. 

These two seemingly dissimilar applications have a common basis—both are examples of the pressure-sensitive release of a chemical. How are these products designed Tiny spherical capsules (microcapsules or microspheres) with a glass or polymer shell are filled with a liquid core and glued onto paper. For a scratch-and-sniff ad, the core of the microcapsules contains a liquid with the desired scent for carbonless paper, a liquid ink or dye is encapsulated within the... 

Still another dosage form is microcapsules, which are tiny droplets of an active agent coated with a permselective barrier polymer, all in the form of a suspension. Microcapsules are conveniently formulated for injection. In such cases the barrier polymer is often chosen to be degradable into innocuous products in the body after the active agent has been dispensed. 

Figure 9.15 illustrates the cathodic polarization curves of the composite nickel-plating bath containing different amounts of microcapsules. The addition of microcapsules enhances polarization and leads to the formation of tiny crystals in the composite coatings. 

Thus, it seems that the use of smaller rrricrocapsules would be beneficial for codeposition as these disperse homogeneously in the bath and improve surface properties such as friction resistance of the plating coating. The problem is that these tiny rrricrocapsules encapsulate too-smaU quantities of core material, and this in turn leads to relatively short periods of controlled release from the microcapsule core. Even rrricrocapsules can lose their functions within a very short period of service ... 

Non-Newtonian multiphase flow problems cover a wide range of industrially relevant applications, and performing accurate, robust, and efficient numerical simulations of them has been the object of numerous research and simulation projects for many years. A perfect representative of such a family of multiphase problems is the microencapsulation or simply encapsulation processes. Microencapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules with many useful properties. In a relatively simplistic form, a microcapsule is a small sphere with a uniform wall around it. The material inside the microcapsule is referred to as the core, internal phase, or fill, whereas the wall is sometimes called a shell, coating, or membrane. Most microcapsules have diameters between a few micrometers and a few millimeters. 

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