Replacing Colloid Chemistry with Nanomorphology: Hierarchical Colloids with Extraordinary Structure Building Capacities

We will discuss emerging technologies for synthesizing complex colloidal particles with advanced structure-building capabilities that can be applied across a wide range of modern technologies. The process of antisolvent precipitation under shear, developed by our group, enables the formation of 12 classes of (bio)polymer structures, including nanoparticles, rods, nanofibers, nanoribbons, sheets, and hierarchical nanomaterials. Many of these complex particles possess unique adhesive, networking, and structure-building capabilities. We will focus on the functionalities enabled by soft dendritic colloids (SDCs) with hierarchical morphology. SDCs exhibit a high excluded volume and strong van der Waals interactions, allowing them to readily form percolated 3D networks. Furthermore, fractal branching and contact splitting phenomena grant SDCs highly unusual properties, such as strong adhesion to surfaces and to each other, gelation at very low volume fractions, and which can be used to form novel adhesives, specialized coatings, and nonwoven sheets. They constitute the basis of homocomposite 3D printing pastes made of biopolymer gels with double networks—specifically, combining molecular and colloidal SDC networks. One emerging application of SDCs with high societal impact is their use as cleaners that capture microplastics for water remediation. SDCs can be integrated into hierarchical biomimetic mesh cleaners inspired by natural seaweed systems. Their architecture enables the adsorption of nano- and micro-scale particles via van der Waals and electrostatic interactions while physically trapping millimeter-scale particles within the mesh openings. Other innovative applications of the highly networked particles include separators and interlayers in Li-S batteries, aerogels with ultralow densities, and reinforced biocomposites.