Cellulose based block polymers for self-assembling layered structures

Coatings are used in many industries as a protective layer against external stress. Marine surfaces must be protected from algae growth, cars against sunlight and scratches, and in many of the fibre-based packages for food, a well-functioning packaging is dependent on applying a coating that provides a barrier against water, grease and gases. To put it another way, what to be protected against varies, but in all cases the coatings should form a sealed film on the surface that needs to be protected. Industrial coatings are largely based on fossil- and/or synthetic components. To meet upcoming legislations and contribute to a sustainable society, the demand for bio-based materials is increasing. Nature includes many polymers that, under certain conditions, can self-assemble into specific structures. A good example is cellulose, which occurs tightly associated in the fiber structure of plants. Biopolymers are also biodegradable and may have unique features that make them attractive in coatings, such as being antibacterial. In BlockLayers we will utilize this and engineer cellulose-based block copolymers which can self-associate in dense, layered structures. The cellulose molecules are linked end to end with another biopolymer (the second block). Cellulose will be responsible for obtaining a dense film, while the other block, with its unique properties, will provide functions such as flexibility, hydrophobicity, antimicrobial and adhesion without affecting the sealed layer of a coating. The BlockLayers concept is ambitious, and the vision is that block copolymers entirely made from natural polymers can replace synthetic block copolymers in the future and provide high-performance coatings. An interdisciplinary team of expertise has been put together and includes researchers from RISE PFI and NTNU-IBT in Norway, as well as experts from LCPO in France and BOKU in Austria.

In the industrial coating sector, there is an increasing demand for environmentally friendly and durable coatings with high performance for end-use segments such as automotive, protective, wood, marine and packaging. In these coatings, synthetic block copolymers are often the main component responsible for creating the sealed layer on the surface in need of protection. Natural polymers having inherent chain properties such as biodegradability and a plethora of stimuli-responsive self-assembly modes, as well as additional functionalities such as being softening, antibacterial and/or antifouling, is an unexplored yet high potential development possibility in coating applications. The BlockLayers project will develop engineered cellulose-based block polymers that can self-assemble into layered (lamella) structures offering a new and innovative approach of forming the sealed layer of coatings and films. The cellulose block will here be main responsible for achieving the ordered structure, while a second block with its unique properties will guide assembly into lamellae structures and add functions such as flexibility, hydrophobicity, antimicrobial and adhesion without affecting the sealed layer. The project is ambitious and include major developments in regards of the preparation of cellulose-based block copolymers and the ability to direct self-assembly into lamellae structures. An interdisciplinary and international team of both young and experienced researchers with complementary knowledge and competences is put together, well set to take on the challenging tasks of the project, taking the concept of block copolymers fully based on natural polymers beyond state of the art and on long-term contributing to more sustainable coatings.