  Active colloids belong to a class of non-equilibrium systems where energy
uptake, conversion and dissipation occurs at the level of individual colloidal
particles, which can lead to particles self-propelled motion and surprising
collective behavior. Examples include coexistence of vapor and liquid-like
steady states for active particles with repulsive interactions only, phenomena
known as motility induced phase transition. Similarly to motile unicellular
organisms, active colloids tend to accumulate at confining surfaces forming
dense adsorbed films. In this work, we study the structure and dynamics of
aggregates of self-propelled particle near confining solid surfaces, focusing
on the effects of the particle anisotropic interactions. We performed Langevin
dynamics simulations of two complementary models for active particles:
ellipsoidal particles interacting through Gay-Berne potential, and rod-like
particles composed of several repulsive Lennard-Jones beads. We observe a
non-monotonic behavior of the structure of clusters formed along the confining
surface as a function of the particle aspect ratio, with a film spreading when
particles are near spherical, compact clusters with hedgehog-like particle
orientation for more elongated active particles, and a complex dynamical
behavior for intermediate aspect ratio. The stabilization time of cluster
formation along the confining surface also displays a non-monotonic dependence
on the aspect ratio, with a local minimum at intermediate values. Additionally,
we demonstrate that the hedgehog-like aggregates formed by Gay-Berne ellipsoids
exhibit higher structural stability as compared to the ones formed by purely
repulsive active rods, which are stable due to the particle activity only.
