• DOI:10.1021/acs.biomac.9b01384
• Corpus ID: 207943524

Designing Cellulose Nanofibrils for Stabilization of Fluid Interfaces.

@article{Bertsch2019DesigningCN,
  title={Designing Cellulose Nanofibrils for Stabilization of Fluid Interfaces.},
  author={Pascal Bertsch and Mario Arcari and Thomas Geue and Raffaele Mezzenga and Gustav Nystr{\"o}m and Peter Fischer},
  journal={Biomacromolecules},
  year={2019}
}

• P. Bertsch, M. Arcari, +3 authors P. Fischer
• Published 12 November 2019
• Engineering
• Biomacromolecules

Particles of biological origin are of increasing interest for the Pickering stabilization of biocompatible and environmentally friendly foams and emulsions. Cellulose nanofibrils (CNFs) are readily employed in that respect, however, the underlying mechanisms of interfacial stabilization remain widely unknown. For instance, it has not been resolved why CNFs are unable to stabilize foams while efficiently stabilizing emulsions. Here, we produce CNFs with varying contour length and charge density to investigate their behavior at the air-water phase boundary. CNFs adsorbing at the air-water interface reduce surface tension and form interfacial layers with high viscoelasticity, which is attributed to the thermodynamic and kinetic stability of CNF stabilized colloids, respectively. CNF adsorption is accelerated and higher surface pressures are attained at lower charge density, indicating that CNF surface charges limit both adsorption and surface coverage. CNFs form monolayers with ≈ 40% coverage and are primarily wetted by the aqueous phase indicating a contact angle < 90°, as demonstrated by neutron reflectometry. The low contact angle at the air-water interface is energetically unfavorable for adsorbed CNFs, which is proposed as potential explanation why CNFs show poor foaming capacity.