Benchmarking supramolecular adhesive behavior of nanocelluloses, cellulose derivatives and proteins

One of the key steps towards a broader implementation of renewable materials is the development of biodegradable adhesives that can be attained at scale and utilized safely. Recently, cellulose nanocrystals (CNCs) were demonstrated to have remarkable adhesive properties. Herein, we study three classes of naturally synthesized biopolymers as adhesives, namely nanocelluloses (CNFs), cellulose derivatives, and proteins by themselves and when used as additives with CNCs. Among the samples evaluated, the adhesion strength was the highest for bovine serum albumin and hydroxypropyl cellulose (beyond 10 MPa). These were followed by carboxymethylcellulose and CNCs (ca. 5 MPa) and mechanically fibrillated CNFs (ca. 2 MPa), and finally by tempo-oxidized CNFs (0.2 MPa) and lysozyme (1.5 MPa). Remarkably, we find that the anisotropy of adhesion (in plane vs out of plane) falls within a narrow range across the bio-based adhesives studied. Collectively, this study benchmarks bio-based non-covalent adhesives aiming towards their improvement and implementation.

Automated summary

The development of biodegradable adhesives is crucial for broader application of renewable materials. In this study, cellulose nanocrystals (CNCs) were found to have exceptional adhesive properties. The highest adhesion strength was observed in bovine serum albumin and hydroxypropyl cellulose samples, followed by carboxymethylcellulose and CNCs, mechanically fibrillated CNFs, tempo-oxidized CNFs, and lysozyme samples. The anisotropy of adhesion among the bio-based adhesives studied was found to be within a narrow range.