Researchers at the National Institute for Materials Science (NIMS) in collaboration with Nihon L’Oréal K.K. have unveiled a groundbreaking product designed to combat the age-old struggle of maintaining frizz-free curls in high-humidity environments. This innovative humidity-responsive hair product boasts shape-memory properties, allowing curls to stay intact even in 80% humidity, rebounding to their original form.
For individuals with curly hair, the battle against frizz in muggy weather is a well-known challenge. Conventional methods, such as flat ironing, often come with limitations and time-consuming efforts, restricting wearers to straight hairstyles. The research team tackled this issue by combining forces with Nihon L’Oréal K.K., resulting in a humidity-resistant hair product with shape memory features.
The foundation of this groundbreaking product is polyvinyl alcohol (PVA), a human-skin-compatible, environmentally friendly polymer known for its water-soluble and malleable properties. The researchers augmented PVA with cellulose microcrystals (CM), leveraging cellulose’s abundance in nature, biodegradability, renewability, and cost-effectiveness. The hydroxyl groups in cellulose form hydrogen bonds with PVA, enhancing mechanical strength, barrier properties, moisture resistance, thermal stability, and UV light absorption.
Innovatively exploring PVA/cellulose composites, the researchers discovered that adding CM to PVA inhibited water molecule absorption into the film, allowing it to maintain low moisture absorption states for extended periods. This breakthrough opened avenues for creating hair curl maintenance products with enhanced shape memory performance in the face of high humidity.
The team evaluated composite films with different PVA/CM ratios, emphasizing moisture absorption and mechanical properties. Films with a CM content between 20% and 25% exhibited superior shape recovery and maintenance, outperforming those with a 33% CM content.
In practical tests, aqueous solutions with varying PVA/CM ratios were applied to natural hair bundles and subjected to high heat for curl creation. The results were remarkable: the treated hair bundles resisted spreading and frizzing, showcasing the product’s potential to maintain hairstyles under high humidity conditions.
When exposed to 80% relative humidity for six hours, the hair coated with the PVA/CM composite maintained its original curly shape better than other compositions, demonstrating a significantly higher shape recovery rate. This pioneering study marks the first evaluation of PVA/CM composites as humidity-responsive shape-memory polymer hair coatings, offering promise as a revolutionary hairstyling agent that resists moisture absorption.
The findings underscore cellulose’s efficacy as a reinforcing filler against humidity and emphasize the critical PVA to CM ratio for achieving both moisture absorption resistance and shape memory properties. This research introduces a novel solution for individuals seeking resilient, frizz-free curls in challenging weather conditions.
