Our research group has recently published a study titled “Fractal Scaling in the Gas‐Phase Agglomeration of Nanowires” in the journal Small (https://doi.org/10.1002/smll.202409673). In this work, led by Nabil Abomailek and Isabel Gómez-Palos along with Cristian Carnicero, María Murillo, Richard Schäufele, and Juan J. Vilatela, we explore how silicon nanowires can self-assemble in the gas phase to form aerogel structures with unique fractal properties.

Using the floating catalyst chemical vapor deposition (FCCVD) technique, the nanowires grow at extremely high aspect ratios (ranging from 10² to 10⁶) while remaining suspended in a gas flow. As they progress downstream in the gas stream, these nanowires tend to agglomerate, resulting in low-density three-dimensional networks that form aerogels. The article demonstrates that this agglomeration follows fractal scaling laws, meaning the resulting geometry is replicated at different scales—a crucial finding for defining the mechanical and conductive properties of the final material.

The team used scanning electron microscopy to capture samples from the gas stream downstream of the reaction zone and characterize the morphology of the aggregates. The results show that the nanowires form fractal aggregates whose Hausdorff index corresponds to classical aerosol agglomeration theories, but applied for the first time to one-dimensional systems at the nanometer scale.