Biopolymer coating on hair substrates
Description of the PhD project
The cosmetic and haircare industries are increasingly seeking sustainable, multifunctional, and high performance materials capable of improving hair appearance and health while reducing environmental impact. In this context, the present project aims to develop an innovative platform based on biopolymer coatings anchored onto hair substrates. The concept combines durable biopolymer sheathing with a stimuli-responsive system capable of delivering advanced hair functionalities such as thickening, anti-frizz protection, dry touch effect for frizzy hair, and temporary coloring. An important aspect of the platform is its reversible behavior, enabling controlled activation and deactivation of hair properties depending on environmental or chemical stimuli.
• The project relies on the use of natural, biosourced, and biodegradable polymers as environmentally friendly alternatives to conventional synthetic hair coatings. These biopolymers will first undergo a pre-functionalization step in order to introduce reactive anchoring groups and hydrophobic fatty chains through covalent grafting. This modification is essential to ensure strong interaction with the hair surface while also improving flexibility, compatibility, and sensory properties. The selection of suitable biopolymers and grafting chemistries will allow the design of adaptive coatings tailored to different hair types and cosmetic applications.
• The second work package focuses on the permanent anchoring of the biopolymers onto the hair fiber. Human hair is a complex keratin-based substrate that requires robust attachment strategies to guarantee coating durability during washing, mechanical stress, and daily use. Covalent bonding approaches will therefore be investigated with methods that have been developed during previous collaborations, to graft the functionalized biopolymers directly onto the hair surface while simultaneously enabling crosslinking within the coating layer. This dual mechanism will create a stable and homogeneous sheath around the hair fiber, improving mechanical strength, smoothness, and volume. The resulting permanent biopolymer coating is expected to provide long-lasting cosmetic benefits while maintaining hair softness and natural appearance.
• The third work package concerns the development of a stimuli-responsive platform capable of reversibly incorporating and releasing active ingredients. In contrast to permanent covalent bonds, weak and dynamic interactions such as hydrogen bonding, electrostatic interactions, or supramolecular associations will be exploited to create reversible functionalities. These responsive systems will enable the encapsulation and controlled release of cosmetic actives including anti-frizz agents, pigments, conditioning molecules, or texture modifiers. External stimuli such as humidity, temperature, pH, or light may trigger the activation or deactivation of specific hair functions, thereby creating a smart cosmetic system.
The final objective of the project is to establish a generic and adaptive coating platform applicable to multiple haircare formulations and treatments. By combining permanent biopolymer sheathing with responsive functionalities, our concept represents a new generation of sustainable and intelligent hair coatings. Beyond cosmetic performance, the project also addresses important environmental challenges by promoting renewable raw materials and biodegradable systems. This research could therefore open new perspectives for advanced eco-friendly haircare technologies with customizable and reversible properties adapted to consumer needs.
Keywords
Hair / Hydrogel / Biopolymer / Stimuli-responsive / Grafting / Click chemistry
Research Unit, UMR number and acronym
ESPCI - Sciences et Ingénierie de la Matière Molle. SIMM. UMR7615
Description of the research Unit/subunit
The SIMM laboratory (Sciences et Ingénierie de la Matière Molle) at ESPCI Paris is a leading interdisciplinary research unit dedicated to soft matter science, at the interface between physics, chemistry, and materials science. Jointly affiliated with ESPCI Paris, CNRS, and PSL University, SIMM develops fundamental and applied research on polymers, colloids, hydrogels, interfaces, and biomaterials.
The laboratory is internationally recognized for its expertise in the design and characterization of responsive soft materials, surface functionalization, adhesion, wetting, and transport phenomena. SIMM combines advanced experimental approaches with strong theoretical and physico-chemical understanding to address challenges in healthcare, energy, sustainable materials, and cosmetics.
The laboratory offers a highly collaborative and international research environment, with numerous academic and industrial partnerships. Its close interactions with companies such as L’Oréal provide an ideal framework for developing innovative and sustainable materials with strong application potential.
Name of the supervisor
Yvette TRAN (yvette.tran@espci.psl.eu)
Name of the co-supervisor
Luca POLACCHI (luca.polacchi@loreal.com)
3i Aspects of the proposal
Intersectoriality
The PhD project has a strong intersectoral dimension through the close collaboration between the SIMM laboratory at ESPCI Paris and L’Oréal Research & Innovation. Initiated this year, the partnership already includes a 12-month postdoctoral project on the grafting of biopolymers onto model substrates and hair fibers using click-chemistry approaches, involving the SIMM (Yvette Tran, Nadège Pantoustier) and S3M laboratories (Amandine Guérinot, Thomas Aubineau) at ESPCI together with L’Oréal’s Hair Fiber & Scalp and Innovation Ingredients departments.
Building on these first developments, the PhD will reinforce knowledge transfer between academia and industry. The project combines expertise in soft matter, polymers, and surface functionalization with industrial objectives related to next-generation haircare technologies. It also offers strong innovation potential for L’Oréal through the development of sustainable, multifunctional cosmetic coatings based on biosourced and biodegradable materials, contributing to high-performance and environmentally friendly haircare solutions.
International
The PhD project has a strong international dimension through the combined environments of L’Oréal, and ESPCI Paris, all of which are highly involved in international research networks and collaborations. As a multinational company, L’Oréal offers access to worldwide research and innovation centers, creating opportunities for international exchanges and industrial secondments. In parallel, ESPCI maintains numerous academic collaborations with leading international institutions in the fields of soft matter, polymers, and biomaterials.
The PhD candidate will therefore benefit from opportunities for mobility abroad, including the international secondment of at least one month. This mobility could take place either within a L’Oréal international research center or through academic collaborations. In particular, a research stay in Asia (Japan or Thailand) could be organized through universities with which Yvette Tran has strong connections. Such a secondment would be highly relevant for the project, especially for developing expertise in gel systems and responsive soft materials.
Interdisciplinarity
The PhD project is highly interdisciplinary, combining concepts and methodologies from chemistry, physics, materials science, and soft matter engineering. A major part of the work focuses on polymer chemistry, including the synthesis, functionalization, and covalent grafting of biopolymers onto hair substrates using click-chemistry approaches. These aspects require expertise in macromolecular design, surface chemistry, and reaction engineering.
The project also strongly integrates physics through the study of hydrogel swelling behavior, interfacial friction, adhesion, and mechanical properties of the biopolymer coatings on hair fibers. In addition, the research involves physico-chemical investigations of stimuli-responsive systems, including reversible interactions, encapsulation/release mechanisms, and environmental responsiveness to humidity, pH, or temperature.
By bridging molecular chemistry with soft matter physics and responsive materials science, the project aims to develop innovative multifunctional coatings for advanced and sustainable cosmetic applications.
Expected profile of the candidate
The candidate should hold a Master’s degree in Materials Science, Physical Chemistry, Polymer Science, or a related field. A strong interest in polymer chemistry, soft matter, surface science, and physico-chemistry is expected. Previous experience through Master’s internships or research projects in materials, polymers, hydrogels, coatings, or surface functionalization will be highly appreciated. Knowledge of characterization techniques for polymers and interfaces would be an asset.
The project requires a motivated and curious candidate who enjoys working at the interface between chemistry, physics, and materials science. The ability to evolve in interdisciplinary and intersectoral environments, combining academic research and industrial innovation, is essential. The candidate should demonstrate autonomy, scientific rigor, strong communication skills, and an interest in sustainable materials and advanced cosmetic applications.
Important dates
Call for applications : from September 1st to October 31st 2026
Eligibility check results : November
3i Committee evaluation results : December
Interviews from the shortlisted candidates with the Selection Committee : January 2027
Start of the PhD : March 1st 2027