  Numerous investigations have demonstrated that standing acoustic waves can
trap particles that range in size from microns to millimeters. Powerful
tweezers may trap clusters of particles rather than single ones because their
trapping radius is substantially larger than the size of the trapped particle.
In this study, clusters of polystyrene particles measuring 450 microns in size
that were suspended in an ionic surfactant solution were trapped at the nodes
of acoustic standing waves. The correlation between surfactant concentration
and threshold radius is examined, and potential mechanisms that could be
responsible for the phenomenon are investigated. The findings demonstrated that
adding polystyrene made clusters unstable and caused them to spontaneously
rupture. Additionally, studies revealed that the cluster began to undergo
spontaneous sequential ruptures after its radius above a particular threshold.
