Protein Adsorption Tailors the Surface Energies and Compatibility between Polylactide and Cellulose Nanofibrils

The state of dispersion and the interactions between a polymer and a filler in a nanocomposite crucially define its properties and performance. The affinity of polylactide (PLA) with vegetable and animal proteins (casein, gelatin, soy protein isolate, and hydrolysate) is investigated and their role as eco-friendly dispersants and compatibilizers of cellulose nanofibrils (CNF) is elucidated. The affinity of the proteins with PLA is determined by using sensograms acquired by electroacoustic (quartz crystal microgravimetry) and optical (surface plasmon resonance) techniques. The surface energy of PLA increases upon protein adsorption while the opposite effect is observed for CNF, under identical experimental conditions. A significant improvement in the thermodynamic work of adhesion for PLA/CNF systems is predicted by application of the denatured proteins at low concentrations (∼20% and ∼15% enhancement with soy protein and casein at pH 3 and pH 8, respectively). We offer a robust method to screen denatured proteins and to tailor the wettability and material compatibility in the synthesis of bionanocomposites based on CNF and PLA.

Publication year: 2017
Authors: A. Khakalo 1, I. Filpponen 1,2, O.J. Rojas 1,3

1 – Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076, Espoo, Finland
2 – Alabama Center for Paper and Bioresource Engineering, Department of Chemical Engineering, Auburn University, Auburn, Alabama 36849-5127, United States
3 – Departments of Chemical and Bimolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States

Published in: Biomacromolecules, 2017, Vol. 18 (4), p. 1426–1433
DOI: 10.1021/acs.biomac.7b00173


altering pH binding on nanofibrillated cellulose (CNF) binding on polylactide (PLA) bound mass casein gelatin hydrolysate protein binding soy protein isolate


Other publications