Surface interactions and rheology of aqueous cellulose-based foams

The aim of this project is to reveal the role of physical-chemical interactions that take place between air bubbles and lignocellulosic materials (fibres, nano- and micro- fibrils, etc.) in the presence of surfactants, polymers, mineral micro- and nanoparticles in aqueous foams. Related phenomena can be translated to the design of corresponding consolidated solids, after foam collapse and water removal, and to the development of new structures and materials that display low weight and high-performance while using comparatively low water volume in their synthesis. SIRAF will investigate the nature of fibre-foam systems, foam generation, decay and consolidation leading to a new class of materials. In this proposed project, the strong partnership between VTT and Aalto University is further strengthened and the extensive know how of fibre foam physics at VTT is combined with the strong surface and colloidal chemistry expertise of Aalto University in a unique way taking benefit from both groups.

Methods: The main methods to be introduced will include the Thin Film Pressure Balance (TFPB), Atomic Force Microscopy (AFM), Surface Laser Light Scattering (SLLS), X-ray Photoelectron Microscopy (XPS), Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), Turbiscan, Dynamic Foam instrument and Foam Forming units as well as other techniques for surface, analytical and chemical characterizations.

Materials: Main “fibre” components to be studied will include lignin-free and lignin containing nanofibrillar cellulose (CNF and LCNF), cellulose nanocrystals (CNC), and wood fibres with different lignin content. Amphiphilic molecules that will stabilize the foam bubbles will include anionic, non-ionic as well as cationic surfactants. Flat surfaces as a model for fibre surfaces will include pure cellulose, lignin and bicomponent films as we have developed and reported in our previous efforts.

Water-free assembly and “light-weighted and strong” are core subjects in the development of the future bioeconomy. This project investigates phenomena affecting materials and processes that offer high performance, energy efficiency, and environmental sustainability.
The aim of this project is to reveal the role of physical-chemical interactions that take place between air bubbles and lignocellulosic materials (fibres, nano- and micro- fibrils, etc.) in the presence of surfactants, polymers, mineral micro- and nanoparticles in aqueous foams.
In this proposed project, the strong partnership between VTT and Aalto University is further strengthened and the extensive know how of fibre foam physics at VTT is combined with the strong surface and colloidal chemistry expertise of Aalto University in a unique way taking benefit from both groups.