Suspended state heteroaggregation kinetics of kaolinite and fullerene (nC) in the presence of tannic acid: Effect of π-π interactions.

The colloidal heteroassociation between natural mineral colloids and engineered nanoparticles (ENPs) can reduce the bioavailability and toxicity of the ENPs. However, the efficacy of this heteroassociation-based entrapment of ENPs depends on the intrinsic material properties of the particles and the physicochemical parameters of the aquatic environment. Natural organic matter (NOM)-induced surface modifications of clay colloids, functionalization of ENPs, and efficiency of counterions as effective coagulants profoundly affect the effectiveness of heteroaggregation-based attenuation of anthropogenic colloids.

Tannic acid- and cation-mediated interfacial self-assembly and epitaxial growth of fullerene (nC) and kaolinite binary graphitic aggregates.

In this study, we investigated the tannic acid (TA)-, Ca-, and mica-enabled interfacial assembly of nC fullerene (FWS) and Na-saturated kaolinite (Na-Kl) with in and ex situ atomic force microscopy (AFM). The epitaxial growth of herringbone motif, two dimensional (2D) chiral clusters and 3D mounds were detected. π-π electron donor-acceptor (EDA) interactions drove the transformation of the FWS, and the symmetry of the muscovite substrate directed the epitaxial ordering of self-assembled herringbone motifs.