Using the Interplay of Particle and Substrate Roughness to Modulate Particle Arrangements in Non-Close-Packed Colloidal Arrays
- 1Darmstadt University of Applied Sciences , , Stephanstr. 7 , ,
- 2Technical University of Darmstadt , , Peter-Grünberg-Str. 12 , ,
- 3European University of Technology, European Union , , https://www.univtech.eu/eutinn
Abstract
Arranging colloidal particles on surfaces with tunable interparticle distances, like in non-close-packed structures (NCPS), is important for many applications. However, controlling their formation remains challenging. Although particle and substrate roughness, along with electrostatic repulsion, affect colloidal interactions, their combined effect on colloidal arrangement remains poorly understood. Therefore, model silica particles with smooth, medium-rough, and rough, virus-like morphologies were synthesized. Virus-like particle synthesis was optimized for controlled roughness (Rq = 1.4–5.1 nm) and low polydispersity (∼5%). Amine-functionalized particles dispersed in water and aqueous LaCl3 solutions were transferred onto gold substrates of two different roughnesses to form NCPS. Only the two roughest particle types (Rq = 4.3 and 5.0 nm) formed three-dimensional aggregates on rough substrates, likely due to pre-aggregation in dispersion, which could be driven by roughness-mediated mechanical interlocking. By varying ionic strength, the effect of electrostatic repulsion on interparticle distances of differently rough particles (Rq = 0.3–2.1 nm) is investigated. The rougher the particles, the less an increasing ionic strength reduces interparticle distances. At low ionic strengths, interparticle distances of rough particles (Rq = 2.1 nm) are independent of ionic strength. Smoother substrates promote lateral mobility for all particles, reducing interparticle distances more strongly for smooth particles. However, aggregation of particles with Rq = 2.1 nm remains almost the same on both substrates (Rq = 0.57 and 1.62 nm), while it increases significantly for smoother particles, suggesting that roughness-induced frictional forces are more important at short distances. These findings reveal that adjusting surface roughness can facilitate controlled particle arrangements.
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BibTeX
@article{barak2026using,
title = {{Using the Interplay of Particle and Substrate Roughness to Modulate Particle Arrangements in Non-Close-Packed Colloidal Arrays}},
author = {Melike Barak and Florian Wolf and Daniel Nachtsheim and Christina Graf},
journal = {ACS omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c04722},
url = {https://europepmc.org/article/PMC/PMC13670335},
note = {CC BY},
}
RIS
TY - JOUR
TI - Using the Interplay of Particle and Substrate Roughness to Modulate Particle Arrangements in Non-Close-Packed Colloidal Arrays
AU - Melike Barak
AU - Florian Wolf
AU - Daniel Nachtsheim
AU - Christina Graf
PY - 2026
DA - 2026/10/01
JO - ACS omega
DO - 10.1021/acsomega.6c04722
UR - https://europepmc.org/article/PMC/PMC13670335
AB - Arranging colloidal particles on surfaces with tunable interparticle distances, like in non-close-packed structures (NCPS), is important for many applications. However, controlling their formation remains challenging. Although particle and substrate roughness, along with electrostatic repulsion, affect colloidal interactions, their combined effect on colloidal arrangement remains poorly understood. Therefore, model silica particles with smooth, medium-rough, and rough, virus-like morphologies were synthesized. Virus-like particle synthesis was optimized for controlled roughness (Rq = 1.4–5.1 nm) and low polydispersity (∼5%). Amine-functionalized particles dispersed in water and aqueous LaCl3 solutions were transferred onto gold substrates of two different roughnesses to form NCPS. Only the two roughest particle types (Rq = 4.3 and 5.0 nm) formed three-dimensional aggregates on rough substrates, likely due to pre-aggregation in dispersion, which could be driven by roughness-mediated mechanical interlocking. By varying ionic strength, the effect of electrostatic repulsion on interparticle distances of differently rough particles (Rq = 0.3–2.1 nm) is investigated. The rougher the particles, the less an increasing ionic strength reduces interparticle distances. At low ionic strengths, interparticle distances of rough particles (Rq = 2.1 nm) are independent of ionic strength. Smoother substrates promote lateral mobility for all particles, reducing interparticle distances more strongly for smooth particles. However, aggregation of particles with Rq = 2.1 nm remains almost the same on both substrates (Rq = 0.57 and 1.62 nm), while it increases significantly for smoother particles, suggesting that roughness-induced frictional forces are more important at short distances. These findings reveal that adjusting surface roughness can facilitate controlled particle arrangements.
SN - 2470-1343
ER -