Architecting Dandelion‐Like Silica Nanotube Superparticles Via Hierarchical Emulsion‐Mediated Sol‐Gel Synthesis

ABSTRACT The assembly of nanotubes into 3D superstructures that combine high active‐site density with efficient mass transport remains a significant challenge. Conventional silica nanotubes tend to tangle and form disordered aggregates, burying functional interfaces and limiting practical applications. Herein, we introduce a hierarchical emulsion‐mediated sol‐gel strategy for the direct construction of dandelion‐like silica nanotube superparticles (D‐SiO 2 NTS) composed of radially aligned nanotube bundles. In a biphasic pentanol–water system, organosilane‐rich droplets and surface‐localized water‐enriched nanodroplets create interfacial microdomains that confine the hydrolysis and co‐condensation of tetraethyl orthosilicate and (3‐mercaptopropyl)trimethoxysilane. This interfacial confinement disfavors lateral deposition and biases growth toward outward anisotropic extension, ultimately yielding dandelion‐like hollow microspheres covered with radially arranged silica nanotubes. The resulting open‐framework architecture provides highly accessible pore channels and abundant thiol groups for post‐functionalization. As a proof of concept, L‐cysteine‐functionalized D‐SiO 2 NTS are immobilized in a glass micropipette to create a confined coordination interface for ionic‐current‐based Cu 2+ sensing. The sensor exhibits a broad detection range (0.1 µM to 100 mM), a low detection limit (0.047 µM), excellent selectivity, and stable performance over nine days. By linking hierarchical interfacial organization to anisotropic hollow growth, this work provides a chemical design principle for directly constructing accessible 3D silica nanotube architectures.