Synergistic interfacial interactions between KH570-modified silica and graphite: From molecular dynamics to aqueous shear exfoliation of graphene nanoplatelets

To address the challenge of low interfacial interaction energy between graphite and water, which hinders effective exfoliation and dispersion of graphene nanoplatelets (GNPs) in aqueous environments, this study introduces silica as an auxiliary medium in shear exfoliation. By modifying the silica surface with KH570, the interfacial interaction with graphite is significantly enhanced. Using molecular dynamics simulations and DFT calculations, we first demonstrate that KH570-modified silica (KH570-SiO₂) exhibits substantially stronger interfacial binding with graphite compared to pure water or unmodified SiO₂/water systems. These interactions enable KH570-SiO₂ particles to act as “rivets” on graphite flakes, effectively transmitting shear stress to promote interlayer sliding and exfoliation. Experimentally, the KH570-SiO₂-assisted shear exfoliation not only facilitates efficient shear transfer but also prevents GNPs from reaggregating through steric hindrance. The resulting GNPs have an average thickness of approximately 4.5 nm and a lateral size of 4–31 µm. This work highlights the critical role of engineered solid–liquid interfaces in overcoming the limitations of aqueous exfoliation. It provides both mechanistic insight and a scalable, eco-friendly strategy for producing structurally controllable two-dimensional materials.