Dendritic surface patterns from Bénard-Marangoni instabilities upon evaporation of a reactive ZnO nanofluid droplet: A fractal dimension analysis

Patryk Wąsik; Annela M Seddon; Hua Wu; Wuge H Briscoe

doi:10.1016/j.jcis.2018.10.077

Dendritic surface patterns from Bénard-Marangoni instabilities upon evaporation of a reactive ZnO nanofluid droplet: A fractal dimension analysis

J Colloid Interface Sci. 2019 Feb 15:536:493-498. doi: 10.1016/j.jcis.2018.10.077. Epub 2018 Oct 25.

Authors

Patryk Wąsik¹, Annela M Seddon², Hua Wu³, Wuge H Briscoe⁴

Affiliations

¹ Bristol Centre for Functional Nanomaterials (BCFN), HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK; School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
² Bristol Centre for Functional Nanomaterials (BCFN), HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK; School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, University of Bristol, Bristol BS8 1TL, UK.
³ School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
⁴ School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK. Electronic address: wuge.briscoe@bristol.ac.uk.

PMID: 30388528
DOI: 10.1016/j.jcis.2018.10.077

Abstract

We present a box counting fractal dimension (FD) analysis of the dendritic patterns obtained under conditions far from equilibrium via rapid evaporation of a sessile drop containing reactive ZnO nanoparticles. These dendrites were manifestations of solidified Bénard-Marangoni (BM) instability convection cells, and we previously noted that their complex hierarchical morphologies were superficially analogous to the foliage of red algae, Spanish dagger, or spider plant. The fractal dimension of the Bénard-Marangoni dendrites was found to vary in the range of 1.77-1.89 and also depend on the size of the Bénard-Marangoni cells. These fractal dimension results were correlated with the morphological details of the Bénard-Marangoni cells and ZnO particle characteristics, providing a quantitative description of such complex surface patterns emerging from the dynamic process of the Bénard-Marangoni instability.

Keywords: Bénard-Marangoni instabilities; Coffee ring effect; Evaporation induced self-assembly; Evaporative drying; Fractal dimension analysis; Reactive nanofluids; Zinc oxide.