Superstructured colloidal materials exploit the synergies between components to develop new or enhanced functions. Cohesion is a primary requirement for scaling up these assemblies into bulk materials, and it has only been fulfilled in case-specific bases. Here, we demonstrate that the topology of nanonetworks formed from cellulose nanofibrils (CNFs) enables robust superstructuring with virtually any particle. An intermixed network of fibrils with particles increases the toughness of the assemblies by up to three orders of magnitude compared, for instance, to sintering. Supramolecular cohesion is transferred from the fibrils to the constructs following a power law, with a constant decay factor for particle sizes from 230 nm to 40 μm. Our findings are applicable to other nanofiber dimensions via a rationalization of the morphological aspects of both particles and nanofibers. CNF-based cohesion will move developments of functional colloids from laboratory-scale toward their implementation in large-scale nanomanufacturing of bulk materials.

Polydisperse smooth and spherical biocolloidal particles were suspended in aqueous media and allowed to consolidate via evaporation-induced self-assembly. The stratification of the particles at the solid–air interface was markedly influenced, but not monotonically, by the drying rate. Cross-sectional imaging via electron microscopy indicated a structured coating morphology that was distinctive from that obtained by using particles with a mono- or bimodal distribution. Segregation patterns were found to derive from the interplay of particle diffusion, interparticle forces, and settling dynamics. Supporting our experimental findings, computer simulations showed an optimal drying rate for achieving maximum segregation. Overall, stratified coatings comprising nano- and microparticles derived from lignin are expected to open opportunities for multifunctional structures that can be designed and predicted on the basis of experimental Péclet numbers and computational order.

We introduce a new type of particle-based membrane based on the combination of lignin colloids (LP) and cellulose nanofibrils (CNF), the latter of which are introduced in small volume fractions to act as networking and adhesive agent. The synergies that are inherent to lignin and cellulose in plants are re-engineered to render materials with low surface energy (contact angle measurements) and that can be rendered water resistant with the aid of wet-strength agents (WSA). Importantly, they are most suitable for anti-oxidative separation (ABTS •+ radical inhibition): membranes with uniform porous structures (air permeability and capillary flow porosimetry) allow effluent oxidation at 95 mL/cm 2 , demonstrating, for the first time, the use of unmodified lignin particles in flexible membranes for active microfiltration. Moreover, the membranes are found to be non-fouling (protein adhesion and activity rate). The inherent properties of lignin, including UV radiation blocking capacity (UV transmittance analysis) and reduced surface energy are further exploited in the development of tailorable and self-standing architectures that are almost entirely comprised of non-bonding LP (solids content as high as 92 w/w%). Despite such composition, the materials develop high toughness (oscillatory dynamic mechanical analysis), owing to the addition of minor amounts of CNF. Multifunctional materials based on thin films (casting), 3D structures (molding) and patterned geometries (extrusion deposition) are developed as a demonstration of the potential use of lignin particles as precursor of new material generation. Remarkably, our observations hold for spherical LPs since a much poorer performance was observed after using amorphous powder, indicating the role of size and shape in related applications.