<p>Regulations have been established across various industries, especially in food and agriculture industries, due to the importance in maintaining optimal humidity level. Excessive humidity led to risk of microbial growth, whereas dry conditions caused adverse effects in product quality. Among all the studies, modification in surface morphology for the increase in surface area and active sites has been reported as a critical approach for the enhancement of humidity sensing. Both amphoteric and cationic surfactants are organic compounds which act as an effective structure regulator for the synthesis of reactive materials, owing to their capability in forming high porosity nanostructure for increase water-surface interaction. In this study, hexamethylenetetramine (HMT) and cetyltrimethylammonium bromide (CTAB) were selected for the modification of surface morphology of tin dioxide (SnO₂) and zinc oxide (ZnO). Precursor solutions of additive-enhanced SnO₂ and ZnO were coated onto glass substrates for morphology characterization. Hygroscopicity test was carried out to examine the interaction between the synthesized nanostructures and the ambient moisture. The effect of additive concentration towards change in material properties was investigated. The observation from the experiment revealed that equimolar additive and reactive material at 0.010&#xa0;M enhanced the water-surface interaction of metal oxide nanostructures significantly. This allows the nanostructures to be used as a reactive material for humidity sensors, enabling applications in humidity-sensitive industries.</p>