Supra-particle Formation By Evaporation of Aerosol Droplets Containing Binary Mixtures of Colloidal Particles: Controlling the Final Morphology

This paper has been published in the Journal of Colloid and Interface Science Volume 682, 15 March 2025, Pages 251-262 DOI: 10.1016/j.jcis.2024.11.155

Hypothesis Supra-particle formation by evaporation of an aqueous aerosol droplet containing nano-colloidal particles is challenging to investigate but has significant applications. We hypothesise that the Peclet number, Pe, which compares the effectiveness of evaporation-induced advection to that of colloidal diffusion, is critical in determining supra-particle morphology and can be used to predict the dried morphology for droplet containing polydisperse nanoparticles.

Experiments Sterically-stabilized diblock copolymer nanoparticles were prepared via polymerization-induced self-assembly (PISA). The systematic study was performed for evaporation rates by levitating an aqueous aerosol droplet and collecting dry supra-particles using electrodynamic balance (EDB) and falling droplet column (FDC), respectively for single-size particles and binary mixtures particles. The supra-particle morphology was characterized using scanning electron microscopy (SEM).

Findings We validate the hypothesis of a higher Pe increases the degree of buckling for both unimodal and bimodal nanoparticle size distributions by employing a higher evaporation rate (K) to increase Pe. However, if Pe is increased by lowering the mean diffusion coefficient (Davg) at a fixed K, the degree of buckling is reduced. For the binary mixture of nanoparticles of differing size, this can be achieved by reducing the concentration of smaller nanoparticles relative to that of larger nanoparticles. Hence consideration of Pe alone is insufficient to reliably predict the final supra-particle morphology.

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Creator(s) Jonathan Reid, Edward Neal, Barnaby Miles, Lukesh Kumar Mahato
Publication date 23 Dec 2024
Language eng
Publisher University of Bristol
Licence Non-Commercial Government Licence for public sector information
DOI 10.5523/bris.1b6bvu1911tx32kdcflkcgteh7
Citation Jonathan Reid, Edward Neal, Barnaby Miles, Lukesh Kumar Mahato (2024): Supra-particle Formation By Evaporation of Aerosol Droplets Containing Binary Mixtures of Colloidal Particles: Controlling the Final Morphology. https://doi.org/10.5523/bris.1b6bvu1911tx32kdcflkcgteh7
Total size 72.4 KiB

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