Tunable Particle Networks with Open Porosity from Amine-functionalized Silica Particles via Interfacial Crosslinking

This work presents a bottom-up strategy for the targeted construction of percolating two-dimensional nanoparticle networks at liquid-liquid interfaces. Using amino-functionalized silica nanoparticles (20 nm) as fundamental building blocks, we demonstrate that interfacial crosslinking with 1,6-hexanediol diacrylate enables the controlled synthesis of extended architectures with tunable connectivity. Systematic variation of reaction time and crosslinker concentration allows for the precise induction of the transition from isolated clusters to fully integrated, global networks. The structural integrity of these assemblies is confirmed via quantitative transmission electron microscopy, with descriptors such as fractal dimension (1.73 ≤ D F ≤ 1.77) and lacunarity providing evidence of percolating geometries consistent with two-dimensional percolation theory. In contrast to classical diffusion- or reaction-limited cluster aggregation, the elevated fractal dimensions observed here originate from chemically controlled fixation rather than purely colloidal agglomeration. Furthermore, finite-size scaling analysis identifies the critical thresholds necessary to engineer global connectivity. These results establish interfacial cluster-cluster crosslinking as a robust assembly tool, providing a rational basis for the fabrication of functional interfacial materials with tailored connectivity, porosity, surface area and functional properties that depend on these factors like conductivity, charge carrier storage capacity or permeability.