Self-assembled filament layers in drying sessile droplets: from morphology to electrical conductivity

Fuente: arXiv
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Autori principali: Schöttner, Johannes, Xie, Qingguang, Nath, Gaurav, Harting, Jens
Natura: Preprint
Pubblicazione: 2025
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author Schöttner, Johannes
Xie, Qingguang
Nath, Gaurav
Harting, Jens
author_facet Schöttner, Johannes
Xie, Qingguang
Nath, Gaurav
Harting, Jens
contents Controlling the deposition of filaments, such as nanowires and nanotubes, from evaporating droplets is critical for the performance of emerging technologies like flexible sensors and printed electronics. The final deposit morphology strongly governs functional properties, such as electrical conductivity, yet remains challenging to control. In this work, we numerically investigate how filament length, stiffness, and concentration affect deposition patterns during the drying process. We compare reaction-limited and diffusion-limited evaporation regimes, demonstrating that their distinct velocity fields and flow magnitudes fundamentally alter filament arrangement. While diffusion-limited evaporation drives the ``coffee-ring effect", compromising network uniformity, reaction-limited evaporation suppresses edge accumulation, promoting centered conductive deposits. We map out the spatial variation of filament alignment - tangential at the contact line, radial in the intermediate region, and random near the center. Longer filaments tend to favour more tangential alignment overall and suppress edge accumulation. We find that by tuning the evaporation regime, filament deposition can lead to significantly lower percolation thresholds and significantly higher conductivity exponents. These results quantify the link between evaporation kinetics and microstructure, providing guidelines for optimizing conductive network formation in printed electronics.
format Preprint
id arxiv_https___arxiv_org_abs_2512_13222
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Self-assembled filament layers in drying sessile droplets: from morphology to electrical conductivity
Schöttner, Johannes
Xie, Qingguang
Nath, Gaurav
Harting, Jens
Soft Condensed Matter
Fluid Dynamics
Controlling the deposition of filaments, such as nanowires and nanotubes, from evaporating droplets is critical for the performance of emerging technologies like flexible sensors and printed electronics. The final deposit morphology strongly governs functional properties, such as electrical conductivity, yet remains challenging to control. In this work, we numerically investigate how filament length, stiffness, and concentration affect deposition patterns during the drying process. We compare reaction-limited and diffusion-limited evaporation regimes, demonstrating that their distinct velocity fields and flow magnitudes fundamentally alter filament arrangement. While diffusion-limited evaporation drives the ``coffee-ring effect", compromising network uniformity, reaction-limited evaporation suppresses edge accumulation, promoting centered conductive deposits. We map out the spatial variation of filament alignment - tangential at the contact line, radial in the intermediate region, and random near the center. Longer filaments tend to favour more tangential alignment overall and suppress edge accumulation. We find that by tuning the evaporation regime, filament deposition can lead to significantly lower percolation thresholds and significantly higher conductivity exponents. These results quantify the link between evaporation kinetics and microstructure, providing guidelines for optimizing conductive network formation in printed electronics.
title Self-assembled filament layers in drying sessile droplets: from morphology to electrical conductivity
topic Soft Condensed Matter
Fluid Dynamics
url https://arxiv.org/abs/2512.13222