**3.1 Physical properties of BPE**

The physical properties determined for the banana peel extract are presented in **Table 1**.

The viscosity of the banana peel extract (BPE) compares favorably well with those previously reported for BPE and other biomaterials. For instance, similar viscosities were reported for extracts from *Citrullus lanatus*, *Phyllanthus*, and banana peels [31, 32]. Viscosity is the property of a fluid that makes it resist flow and sustain frictional force. It is an important property of a good inhibitor, which makes it stick to the surface of metals thereby forming a protective barrier against corrosion. It represents the ability of the extract to adhere longer to metal surfaces, thus enhancing corrosion inhibition. Corrosion inhibitors often contain one or more surfactants, which lowers the surface tension of corrosive fluids [33]. Similarly, the flash point of BPE extract is within the range reported by Kliskic et al. [34] and Betiku et al. [35]. This indicates the flammability or combustibility of the inhibitor.
