Enhancing the adhesion and retention of microcapsules on human hair

Marques de Marino, Javier (2018). Enhancing the adhesion and retention of microcapsules on human hair. University of Birmingham. Ph.D.

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Abstract

Perfume-filled microcapsules (PMC) are intended to be used in personal care products to provide a pleasant smell to consumers after washing their hair. It is essential to understand the interactions between the PMC and the untreated and bleached hair. The discovery of the adhesion mechanism would provide insight into the strategies for enhancing the performance of PMC on hair.

The mechanism of adhesion and retention of PMC on two types of hair fibres (untreated and bleached) and their surface modifications to enhance the adhesion were investigated and explained in this work. The main equipment used in the investigation were: an atomic force microscope (AFM), a parallel plate flow chamber (PPFC) and a shower replica.

It was found a dramatically decrease of the interactions between the hair and the PMCs when the hair had been previously bleached. The hydrophobic interactions were considered the main mechanism for this reduction but also the electrostatic interactions and hydrogen bonding were not discarded as a route to improve the adhesion and the retention of PMCs.

In order to improve the adhesion between PMC and human hair, different types of silicones and cationic polymers were used to coat the hair and the capsule. An improvement was found up to 400% using polyquaternium-7 or aminosilicone. The increase of the adhesion with these polymers confirmed the importance of hydrophobic interactions as the main driving mechanism but also the significant role of hydrogen bonding in the interactions between PMCs and hair fibres.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):