In nature, fast, high-power-density actuation can be achieved
through the release of stored elastic energy by exploiting
mechanical instabilities in systems including the closure of the
Venus flytrap1
and the dispersal of plant or fungal spores2.
Here, we use droplet microfluidics to tailor the geometry of a
nanoscale self-assembling supra-molecular polymer to create
a mechanical instability. We show that this strategy allows
the build-up of elastic energy as a result of peptide selfassembly, and its release within milliseconds when the buckled
geometry of the nanotube confined within microdroplets
becomes unstable with respect to the straight form. These
results overcome the inherent limitations of self-assembly for
generating large-scale actuation on the sub-second timescale
and illuminate the possibilities and performance limits of
irreversible actuation by supra-molecular polymers.