Chemistry Reference
In-Depth Information
Fig. 7.17
Ensemble averaged MSDs for different confinements of droplets as shown in the
inset
of the legend
In this section, we presented results which demonstrate that the droplet squirmers
might be a versatile table top tool to study the statistical mechanics of SPPs in general
and not just the hydrodynamics of microswimmers. However, improvements in the
experimental techniques such as changing the linear channel geometry to a circular
one with more droplets and having an improved chemical drive of the droplets to
increase the observation time and thus record many more collisions between the
particles will definitely help to improve the statistical inferences.
7.4 Summary and Outlook
We have demonstrated that the artificial squirmer described in Chap.
6
is particulary
well suited for the study of collective phenomena of microswimmers. The collec-
tive behaviour of these squirmers shows strong velocity correlations and effective
diffusivities, which are qualitatively similar to recent simulation results. However,
distinct differences were observed which can be attributed in part to simplifications
that had to be made in the simulations. The interactions with passive tracer parti-
cles were shown to result in closed loops for the tracer trajectories, which can have
implications in understanding flow field from tracer properties. Finally, studying
their interactions with walls and in confinement, we were able to demonstrate the
suitability of the droplet swimmers for studies of a range of non-equilibrium phe-
nomena. While the results presented in this chapter were able to address some open
questions concerning the collective dynamics of microswimmer, they open the door
to many more possibilities in the future. As we discussed earlier, we would like to
look for phase transitions in the swimmer density going from individual to collective
dynamics. Such a study will only benefit from the complete characterization of the
flow fields of the squirmer, in addition to improving the ability to tune the motion
of the swimmer better. While some of the experiments to address these issues are
