Biobased Nanomaterials─The Role of Interfacial Interactions for Advanced Materials

Abstract

This review presents recent advances regarding biomass-based nanomaterials, focusing on their surface interactions. Plant biomass-based nanoparticles, like nanocellulose and lignin from industry side streams, hold great potential for the development of lightweight, functional, biodegradable, or recyclable material solutions for a sustainable circular bioeconomy. However, to obtain optimal properties of the nanoparticles and materials made thereof, it is crucial to control the interactions both during particle production and in applications. Herein we focus on the current understanding of these interactions. Solvent interactions during particle formation and production, as well as interactions with water, polymers, cells and other components in applications, are addressed. We concentrate on cellulose and lignin nanomaterials and their combination. We demonstrate how the surface chemistry of the nanomaterials affects these interactions and how excellent performance is only achieved when the interactions are controlled. We furthermore introduce suitable methods for probing interactions with nanomaterials, describe their advantages and challenges, and introduce some less commonly used methods and discuss their possible applications to gain a deeper understanding of the interfacial chemistry of biobased nanomaterials. Finally, some gaps in current understanding and interesting emerging research lines are identified.

Enhancing Water Resistance in Cationic Cellulose Nanofibril Adhesive with Natural Rubber Latex

“…In addition to favorable interfacial adhesion (CCNF–substrate), the cohesion mechanical strength of bulk adhesives is a crucial point for preventing cohesive failure. Charged cellulose nanofibrils can absorb and retain water due to the ionic osmotic pressure. ,, Therefore, swelling of adhesives prepared only with charged CNFs can cause a significant mechanical property loss, impairing their performance, since penetration of water molecules dissociates hydrogen bonds among the nanofibers . Several strategies increase the strength of cellulosic materials in water or high-humidity environments, including covalent bonds − and noncovalent interactions. − Here, we propose a simple mixing method for oppositely charged particles in water to overcome this issue.…”

“…Charged cellulose nanofibrils can absorb and retain water due to the ionic osmotic pressure. 13,47,48 Therefore, swelling of adhesives prepared only with charged CNFs can cause a significant mechanical property loss, impairing their performance, 49 since penetration of water molecules dissociates hydrogen bonds among the nanofibers. 50 Several strategies increase the strength of cellulosic materials in water or high-humidity environments, including covalent bonds 51−53 and noncovalent interactions.…”

Redesigning Natural Materials for Energy, Water, Environment, and Devices

“…Specifically, an Electrical Double Layer (EDL) is generated after the hydroxyl groups of cellulose molecules partially deprotonate under aqueous conditions (Figure 4b). 82,83 When the channels among cellulose fibers have a radius comparable to the characteristic length of the electrostatic potential (Debye length λ d ), the overlapped diffusing layers of the EDLs create the unipolar solution of counterions and electrostatically repel ions carrying charge with the same sign of the charged wall. The potential difference across the EDL affects the diffusion of ions from the electrolyte solution into the cellulose material and the migration of the ions within the channels.…”

“…The multiscale channels of cellulose can be categorized into three dimensions for ion regulation: (1) regular bulk ion conduction out of Debye length λ d (>100 nm); (2) nanofluidic ion transport due to Electrical Double Layer (1–100 nm); and (3) Ångström-scale ion transport upon the intercalation of ions between the cellulose molecular chains (<1 nm). Specifically, an Electrical Double Layer (EDL) is generated after the hydroxyl groups of cellulose molecules partially deprotonate under aqueous conditions (Figure b). , When the channels among cellulose fibers have a radius comparable to the characteristic length of the electrostatic potential (Debye length λ d ), the overlapped diffusing layers of the EDLs create the unipolar solution of counterions and electrostatically repel ions carrying charge with the same sign of the charged wall. The potential difference across the EDL affects the diffusion of ions from the electrolyte solution into the cellulose material and the migration of the ions within the channels.…”

Urushi as a Green Component for Thermally Curable Colloidal Lignin Particles and Hydrophobic Coatings

“…LNPs have a well-defined spherical shape and exhibit colloidal stability due to the electrostatic repulsion forces of carboxylic acid and phenolic hydroxyl groups enriched on their surface, which prevents their aggregation in aqueous dispersions (pH 3–9) and provides a high surface area to mass ratio . This anionic surface charge has been used for the physical modification of LNPs via adsorption of positively charged compounds such as enzymes or polymers, as well as improving the compatibility within polymeric matrixes. − Recently, photonic materials with a variety of structural colors have been achieved with LNPs. − These developments have transformed LNPs into a thriving research field in many different applications such as biomedicine, , water purification, composites, , and surfactants, , among others. − However, when it comes to chemical functionalization of LNPs in the dispersion state, limitations associated with their dissolution in basic pH > 10 (due to the deprotonation of phenolic groups) and aggregation in acidic media pH < 2.5 (due to the neutralization of carboxylic acid groups) restricts their functionalization and potential end-uses . To overcome these limitations, our group and others have reported various methods for the stabilization of LNPs via internal cross-linking by the addition of a cross-linker during their supramolecular assembly, , the use of oxidoreductive enzymes such as laccases, , or by endowing LNPs with a hydration barrier derived from fatty acids. , Among them, the use of fatty acids emerges as one of the most attractive approaches to prepare stable hybrid particles in a high yield without the use of fossil-derived cross-linking agents, which is critical for technical applications that require large quantities of lignin, such as waterbone dispersion coatings .…”