ABSTRACT
OBJECTIVE: Coacervates are inevitably formed on scalp on using hair washing products. Our goal was to analyse the coacervates in detail to identify the part responsible for scalp stimulation. METHODS: Shampoo that increases coacervate formation was applied to in vitro skin and was washed. The residue was then analysed using Fourier transform infrared spectroscopy-focal plane array (FTIR-FPA) and X-ray photoelectron microscopy (XPS). And HaCaT cells were used for irritant test of coacervate. RESULTS: Through this research, it was confirmed that the coacervate was a macromolecule structurally similar to a cationic polymer and contains an anionic surfactant. Its anionic surfactant was structurally semi-stable so that it released onto scalp when it absorbs moisture. CONCLUSION: Coacervate releases sulphate bonding into the matrix when it is exposed to water. Thus, the scalp stimulation would be expected.