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Surface and interfacial tension is a force that keeps a fluid together at the air/ fluid and fluid/oil interface respectively (Figure 1). It is the intermolecular force of attraction between adjacent molecules, expressed in force per unit width as dynes centimetre-1 (dynes cm-1) or milliNewtons metre (mN m-1). Water, at ambient temperature, has a high surface … Read more

Optical microscopy is one of the techniques which involve the use of polarized light to detect liquid crystalline structure (Figure 1). A polarizing microscope equipped with a heating stage permits visual observation of the phase transformations, from micelles phase through liquid crystal phase (Figure 2). The transformation could be as a result of the change of temperature … Read more

Most of the products which we encountered daily are homogeneous mixtures of chemical species dispersed at a molecular level. Some of these particles are so small that they are invisible to our naked eyes. For example, a microemulsion solution appears to be clear and colourless. Some of the examples of dispersion of particles, which we … Read more

Pantha rei” as the Greek philosopher said everything flows. We live in a world whereby everything flows in a matter of time. To describe these flows, we have come up with a variety of terms such as flowing, gushing slipping, dripping, running, squirting, oozing, seeping, etc. and we can immediately associate each word with the motion … Read more

Thermal analysis is defined as the measurement of changes in chemical or physical properties of a sample as a function of temperature or time in a controlled atmosphere. A special instrument called the TGA (thermogravimetric analysis) which consists of a furnace, weight balance and photodiode sensors is designed to make such measurements (Figure 1). TGA measures … Read more