Evaporation effects in elastocapillary aggregation

TL;DR

This paper investigates how evaporation influences the aggregation dynamics of elastic objects driven by surface tension, revealing that evaporation accelerates contact formation but reduces cluster size.

Contribution

It introduces a lubrication theory-based model for elastocapillary aggregation with evaporation, highlighting the impact of evaporation rate on aggregation speed and cluster size.

Findings

Higher evaporation rates lead to faster aggregation and contact formation.

Increased evaporation reduces the number of elements in each cluster.

The results are quantitatively explained by a two-body problem comparison.

Abstract

We consider the effect of evaporation on the aggregation of a number of elastic objects due to a liquid's surface tension. In particular, we consider an array of spring--block elements in which the gaps between blocks are filled by thin liquid films that evaporate during the course of an experiment. Using lubrication theory to account for the fluid flow within the gaps, we study the dynamics of aggregation. We find that a non-zero evaporation rate causes the elements to aggregate more quickly and, indeed, to contact within finite time. However, we also show that the number of elements within each cluster decreases as the evaporation rate increases. We explain these results quantitatively by comparison with the corresponding two-body problem and discuss their relevance for controlling pattern formation in elastocapillary systems.