Developing barrier coatings with cellulose derivatives

The goal is to be able to design coatings with desired barrier properties, by controlling the structure development. We aim to develop knowledge on novel barriers from natural resources, with applications ranging from packaging and foods to medical devices and pharmaceutics.
Thin films of polymers from natural resources (e.g. cellulose) can be used as barrier coatings for applications in pharmaceutics, medical devices, packaging and food products. The barrier films may reduce gas transport through a package or control drug delivery from a tablet.
Cellulose derivatives show great promise for forming these coatings and are used, for instance, to extend the release of drugs. Such films can be formed by drying a thin layer of a solution containing one or several cellulose derivatives.
Polymer mixtures most commonly separate into different compartments (phase separation) as the solvent evaporates. By mixing two cellulose derivatives that phase separate, one of which is water soluble, a porous coating is obtained after the film is exposed to liquids in the gastrointestinal tract. This allows the drug to be slowly transported through the pores of the coating, thus maintaining a therapeutic level in the blood for an extended time. An important, yet evolving, area is related to our understanding of the relationship between the microstructure and the transport of molecules through thin films, as well as how these structures are formed.
What effects will the molecular weight have on the final film structure and barrier properties?
How do the film microstructures develop during solvent evaporation and what mechanisms determine the morphology?
Does the molecular weight affect the specific rate (kinetics) of the phase separation process and can we utilize the kinetics and mechanisms of phase separation to control the structures and properties of films?


Page manager Published: Mon 28 Oct 2013.